Meis2 is essential for cranial and cardiac neural crest development
© Machon et al. 2015
Received: 11 August 2015
Accepted: 3 November 2015
Published: 6 November 2015
TALE-class homeodomain transcription factors Meis and Pbx play important roles in formation of the embryonic brain, eye, heart, cartilage or hematopoiesis. Loss-of-function studies of Pbx1, 2 and 3 and Meis1 documented specific functions in embryogenesis, however, functional studies of Meis2 in mouse are still missing. We have generated a conditional allele of Meis2 in mice and shown that systemic inactivation of the Meis2 gene results in lethality by the embryonic day 14 that is accompanied with hemorrhaging.
We show that neural crest cells express Meis2 and Meis2-defficient embryos display defects in tissues that are derived from the neural crest, such as an abnormal heart outflow tract with the persistent truncus arteriosus and abnormal cranial nerves. The importance of Meis2 for neural crest cells is further confirmed by means of conditional inactivation of Meis2 using crest-specific AP2α-IRES-Cre mouse. Conditional mutants display perturbed development of the craniofacial skeleton with severe anomalies in cranial bones and cartilages, heart and cranial nerve abnormalities.
Meis2-null mice are embryonic lethal. Our results reveal a critical role of Meis2 during cranial and cardiac neural crest cells development in mouse.
KeywordsMeis2 Neural crest Persistent truncus arteriosus Craniofacial skeleton Cranial nerves
Neural crest cells (NCC) represent a multi-potent embryonic cell population that generates a very diverse range of cell types including cranial nerves, neurons and glia of the peripheral nervous system, enteric neurons, melanocytes, cranial bones and cartilages [1, 2]. The first NCC appear at the neurula stage in the neural plate border region. As the neural tube closes in mouse, NCC delaminate from the regions of neural plate border and ectomesenchyme after epithelial-to-mesenchymal transition (EMT) and migrate to various developing organs. The very broad differentiation potential of NCC provides a complex model of cell type specification and migration and the gene regulatory network determining the spatiotemporal control of NCC diversification has been extensively studied. For instance, the NCC population is specified by the set of transcription factors Sox9, Sox10, FoxD3, Snai2 together with Msx1, Pax3/7 or Zic1 in the neural plate border . These effector genes are regulated by coordinated action of signaling pathways such as Wnt, Bmp and Fgf from the adjacent paraxial mesoderm and non-neural ectoderm [2, 4]. The differentiation potential of NCC is spatially determined by their position along the rostrocaudal axis. In a simplified view, cranial NCC coming from mesencephalic and rhombencephalic regions generate head bones, cartilages, cranial nerves and selected connective tissues [5, 6]. Vagal NCC from the area of somites 1-7 are destined to the enteric nervous system. Cardiac NCC (somites 1-4) are involved in septation of the cardiac outflow tract  and trunk NCC form sensory and sympathetic ganglia. The current debate, however, favors the scenario proposing that originally multi-potent NCC stem cells are exposed to different environmental cues along the rostrocaudal axis that spatiotemporally restrict their differentiation potential [1, 8].
Meis proteins are transcription factors that are orthologous to the Drosophila homothorax (Hth) protein. They contain a TALE (three-amino-acid loop extension) sub-class of the homeodomain that binds to DNA. In humans and mice, three homologues Meis1, Meis2 and Meis3 have been identified  and it has been shown that they directly bind to Pbx proteins [10–12]. The Meis/Pbx protein complex binds to DNA through respective Meis- and Pbx-consensus binding sites thereby regulating transcription. The Meis/Pbx complex plays important roles during development of several organs including limbs [13, 14], heart [15, 16], lens , pancreas  and hindbrain [19–22]. Hox genes are among the target genes of Meis-Pbx control via modulation of histone acetylation indicating recruitment of Hox proteins as cofactors of Meis-Pbx complex [23, 24].
Mice lacking Meis1 display liver hypoplasia, hemorrhage, impaired erythropoiesis and eye defects, and die by the embryonic day (E) 14.5 [25, 26]. Although a substantial amount of data have been reported on the role of Meis1 in organogenesis, hematopoiesis and leukemia induction, the function of the other homologs, Meis2 and Meis3, is much less clear. Chicken Meis2 has a specific role in determining cell fate in the midbrain-hindbrain boundary by controlling the expression of Otx2  and it also affects proliferation of retinal progenitor cells . Several recent reports in various model systems indicated that Meis2 may play a role in neural crest cells. Meis2 was identified as one of the key transcription factors in the gene regulatory network driving differentiation of human embryonic stem cells towards cardiovascular cell types, and this was further confirmed by knock-down experiments in zebrafish . Morpholino-based screens in zebrafish revealed the importance of Meis1 and Meis2 factors during craniofacial development . Moreover, gene expression analysis of EMT in endocardial cushions identified Meis2 among enriched genes . In this context it is very interesting that some human disorders displaying cleft palate and heart developmental defects have been linked to mutations in the Meis2 locus [30–33]. Nonetheless, a clear picture of the Meis2 function based on a genetic mouse model is still missing.
In the present study, we examined the role of Meis2 during embryogenesis by generating conditional knock-out mice. We studied morphological defects after either zygotic inactivation of the Meis2 allele or NCC-specific conditional knock-out using AP2α-IRES-Cre. We conclude that hemorrhaging most probably causes embryonic lethality. Further, many embryonic defects in the tissues derived from neural crest in systemic Meis2-nulls were recapitulated upon conditional deletion of Meis2 in NCC suggesting an indispensable role of Meis2 in NCC.
Meis2-/- embryos are lethal and display hemorrhaging
A detailed inspection of internal organs in mutant embryos revealed that the liver was the most impaired organ with a destructed cellular organization in large regions (Additional file 1: Figure S1C-D). These impaired regions contained almost no erythrocytes labelled with Ter119 but many apoptotic cells as shown by TUNEL assay (Additional file 1: Figure S1E-F). Surprisingly, Meis2 was not found to be expressed in the fetal liver while Meis1 was readily detectable (Additional file 1: Figure S1A). Based on this we suggest that the observed cell death in the liver is a consequence of strong hemorrhaging in the whole embryo that leads to anemia and apoptosis primarily in the liver and may be a cause of the embryonic lethality. Having observed anemia in Meis2-/- embryos we further pursued the possibility that Meis2 may influence embryonic hematopoiesis similarly to Meis1 that controls proliferation of hematopoietic stem cells in the fetal liver and is also essential for megakaryocyte viability [25, 26, 34]. We therefore mapped the expression of Meis2 and Meis1 in the area of the aorta-gonad-mesonephros (AGM), the site of origin of embryonic hematopoietic stem cells. As shown in Additional file 1: Figure S2B, neither Meis2 nor Meis1 were observed in endothelial cells labelled with CD31 but both proteins were abundant in the mesenchyme surrounding the endothelial wall of the dorsal aorta. We further found that circulating hematopoietic progenitors labeled with anti-Runx1 antibody did not express Meis2 (Additional file 1: Figure S2C). Finally, we carried out erythroblast cultures derived from the fetal liver and found no differences in the growth and differentiation of liver erythroid progenitors between Meis2-/- and controls (data not shown). As Meis2, in our hands, was not detected in hematopoietic progenitors neither in the AGM nor in the fetal liver, we hypothesize that the anemia in the mutants originates from extensive bleeding or defective circulation rather than defects in hematopoiesis.
The lack of Meis2 results in fetal heart malformation
In the heart of Meis2-/- embryos at E12.5, we observed incomplete septation of the outflow tract that normally separates the aorta from the pulmonary artery. This defect is known as persistent truncus arteriosus (PTA) and was observed in all analyzed mutants (n = 8 litters, 14 mutants) (Fig. 1d). To correlate the observed defects with the expression of Meis2, we carried out immunohistochemistry on sections of embryonic heart at E13 using anti-Meis2 antibody. As shown in Fig. 1e, a remarkably strong presence of Meis2 was observed in the aortic and pulmonary valves. Strikingly, these valves were lost in the Meis2-/- heart (arrowheads). To visualize the PTA in the Meis2-/- outflow tract, we used antibody against α-smooth muscle actin (SMA). Stained heart sections confirmed the PTA but SMA appeared normally expressed in the mutant heart (Fig. 1f).
Neural crest cells express high levels of Meis2
Conditional deletion of Meis2 in neural crest cells leads to a defective heart outflow tract
Meis2 affects cranial nerve development
Development of cranial cartilage is perturbed in Meis2-null embryos
Meis2 does not affect proliferation and expression of main determinants of NCC
We also analyzed the number and spatial distribution of migrating NCC using anti-Sox9 antibody at E10.5. Sox9-positive NCC are abundant in the embryonic head mesenchyme and pharyngeal arches, however, their quantification did not reveal significant changes between controls and mutants (Additional file 1: Figure S4A). Further, we examined cell proliferation using antibodies against PCNA and PH3 on head sections. Again, quantification of all proliferating cells (all PCNA+ or PH3+) or proliferating NCC (Sox9+/PCNA+) did not differ between controls and mutants (Additional file 1: Figure S4B-D). Finally, apoptosis, as measured by anti-Cas3 immunohistochemistry at E10.5, was not significantly altered in the mutants (Additional file 1: Figure S4E). In summary, Meis2 absence did not result in dramatic changes in cell proliferation and viability at E10.5.
Systemic Meis2 mutants show aberrant position of FoxD3 and Sox9
In this study, we showed that the transcription factor Meis2 is abundant in NCC and it is essential for their function. The embryonic lethal phenotypes of mutant mouse embryos of Meis2 and its paralogue Meis1 are similar in the timing of death and in strong hemorrhaging. Meis1 is expressed hematopoietic stem cells in the fetal liver, the primary organ of hematopoiesis at E13. Various assays showed defects in erythropoiesis providing explanation for anemia in Meis1 mutants [25, 26]. In contrast, we did not detect Meis2 in the fetal liver and in hematopoietic progenitors in the dorsal aorta. We therefore speculate that hemorrhaging in Meis2-/- embryos caused destructive changes primarily in the fetal liver that is highly sensitive to low oxygen. Impaired function of the liver may lead to failure in erythropoiesis and thus bleeding rather than defects in hematopoiesis in Meis2 mutants may cause lethality. Despite 83 % sequence identity of Meis1 and Meis2 and the almost identical homeodomain, they acquired different functions during evolution probably due to distinct expression patterns.
Stankunas and colleagues [15, 45] showed that various combinations of mutant alleles of Pbx1/2/3 or Meis1 exhibit cardiac anomalies in the outflow tract or in the septation of ventricles implying that cardiac NCC require transcriptional control by combinatory Meis/Pbx complexes. Along this line, zebrafish Meis2 genes influence development of heart and cranial skeleton [16, 28]. The data presented here extend our knowledge about the role of Meis/Pbx complexes controling the fate of NCC. Apart from the previously proposed function in cardiac neural crest, we suggest that a similar transcriptional control network takes place in cranial NCC including chondrogenic and neuronal lineages. Our data represent the first loss-of-function study of Meis2 in mouse and may in fact serve as a disease model for certain human developmental disorders. Intriguingly, several reports describe patients with Meis2 mutations who display disorders such as the cleft palate, septal defects in the heart or intellectual disabilities [30–33].
Pax3 is expressed in the neural plate border and plays an important role in cardiac NCC as documented by conditional knock-out studies in mouse . A specific Pbx1/Meis1 complex has been reported to directly regulate Pax3 in premigratory NCC in rhombomeres, in which cardiac NCC originate, linking Pbx1-Pax3 regulatory hierarchy with the OFT defects in Pbx1-/- embryos . We did not see reduced Pax3 expression in Meis2-/- at E10.5 although Pax3-positive trigeminal ganglions were shrunken in systemic mutants. Nor could we detect Pax3 in the wild-type OFT at E10.5. It is possible that Meis2 and Pax3 are co-expressed in earlier NCC in which these factors may cooperate during NCC differentiation.
Our experiments utilizing conditional mutants AP2α-Cre/Meis2 cKO confirm defects in tissues derived from cardiac and cranial NCC such as the OFT or craniofacial cartilage. However, the phenotypes in cKO appeared in some cases weaker than in systemic mutants. PTA, for instance, was never found in conditional mutants while all systemic mutants displayed defective septation of the OFT. It is important to note that we still found a substantial amount of Meis2 protein after conditional deletion in the areas that are in close vicinity of AP2α-Cre targeted regions (mapped in the ROSA26 reporter) in which we observed effective inactivation. Standby Meis2-positive cells may be involved in forming the truncus septum. Although AP2α-Cre mouse is the earliest driver for NCC , we cannot exclude the possibility that a minor NCC population forms before AP2α-Cre mediated recombination and thus it is not targeted. Another possibility is that neighboring non-NCC cells expressing Meis2 participate in the truncus septation. In this context it is interesting to note that systemic Pax3 KO display the PTA while Wnt1-Cre or AP2α-Cre cKOs of Pax3 show valve defects but normal separation of aorta and pulmonary arteries . Moreover, the PTA defects were also seen in systemic Pbx1-3 mutants; the data from Pbx cKOs are not available [15, 45]. The fact that the truncus septation may partially originate from non-NCC population is supported by the report of Bai and colleagues  who observed PTA in Mef2c-Cre/Bmp4/7, a Cre driver not normally used for NCC targeting.
Altered proliferation, apoptosis or significant changes in expression of transcription factors determining NCC (Sox9, Sox10, Tfap2, Pax3, Mitf) were not detected between critical stages E10.5-E11.5 in our hands. Meis2 may influence late phases of NCC differentiation (including cell proliferation and viability) that is required for proper formation of the OFT or for differentiation of osteochondral progenitors.
We hypothesize that Meis2 absence may be compensated by Meis1 which may rescue some defects during earlier phases of NCC development. Meis2 deficiency is thus reflected in the areas and stages in which the Meis2 function is unique, e.g. during craniofacial development. Meis proteins may diversify in their expression pattern after the initial NCC specification and acquire unique function, for instance, during formation of the OFT and cartilage. In order to test this hypothesis it will be necessary to generate and analyze Meis1 and Meis2 conditional double mutants that may reveal potentially earlier role of Meis factors during NCC development.
Even though we did not see a major difference in Sox9 expression in early embryos, anomalies in the craniofacial skeleton of Wnt1-Cre/Sox9 cKO  and our AP2α-Cre/Meis2 cKO are similar in the mandible, tongue, the otic capsule and the hyoid bone. This suggests that Sox9 and Meis2 cooperate in a similar differentiation process during chondrogenesis. It remains to be elucidated what genes are direct targets of Meis factors. Altogether, our loss-of-function studies show that Meis2 transcription is an important player in the gene regulatory network determining differentiation of cardiac and cranial NCC.
Generation of Meis2 null mice
The LoxP recognition elements for the Cre recombinase were inserted in the introns 2 and 6 of the Meis2 gene at the Gene Targeting & Transgenic Facility, University of Connecticut, USA. Transgenic mice termed Meis2 cKO were created by standard techniques using homologous recombination in mouse embryonic stem cells (129SvEvTac/C57BL/6 J F1) also at the Gene Targeting & Transgenic Facility. A neomycin selection cassette was removed using FLP-FRT recombination. Meis2 cKO were crossed to Hprt-Cre mice (strain 129S1/Sv-Hprttm1(cre)Mnn/J, stock 004302, The Jackson Laboratory) with the zygotic activity of the Cre recombinase to obtain animals that were heterozygous for Meis2 (Meis2+/-) in the mixed genetic background. Primers for genotyping Meis2+/- alleles: Mrg1-lox-F (forward) GAGGGGACAGTGGGTAAACA, Mrg1-frt-R (reverse) TCAGACCCAGGAATTTGAGG, a PCR product of 256 bp. Wild-type allele: Mrg1-frt-F GCAAGGGTGCTGAGGTTAAA and Mrg1-frt-R TCAGACCCAGGAATTTGAGG, a PCR product 235 bp. (Fig. 1a). Alternatively, Mrg1-lox-F GAGGGGACAGTGGGTAAACA, Mrg1-lox-R GCGTTGCAGCTCACAAGAAT, a PCR product of 142 bp.
All procedures involving experimental animals were approved by the Institutional Committee for Animal Care and Use (permission #PP-071/2011). This work did not include human subjects.
Embryos were fixed in 4 % paraformaldehyde overnight at 4 °C. 8-10 μm cryosections or 5-μm (paraffin-embedded) sections were permeabilized in 0.1 % Triton X-100 in PBS (PBT). After blocking sections were incubated overnight in a primary antibody (1 % BSA in PBT), washed with PBS and incubated with a fluorescent secondary for 1 h. Nuclei were visualized by DAPI (4,6-diamidino-2-phenylindol, 0.1 μg ml− 1, Roche). Primary antibodies: anti-Meis2 and anti-Meis1 (a gift from Dr. Buchberg), anti-Myl7 (1:250, Santa Cruz), smooth muscle actin (SMA) (1:1000, Sigma), Sox10, Twist1 (all Santa Cruz Biotech), 2H3 (neurofilaments), 3B5 (Tfap2a) and Pax3 (all DSHB), anti-alpha sarcomeric actin clone 5C5, anti-alpha smooth muscle actin clone 1A4 (both Sigma), anti-Myl7 (H60) (Santa Cruz Biotech), Mitf (a gift from Dr. H. Arnheiter), anti-Ter119 (BD Pharmingen). Secondary antibodies: anti-mouse (-rat, -rabbit) Alexa Fluor488 or 594 (Life Technologies). Biotinylated-anti-mouse, -anti-rabbit, -anti-rat (Vector Laboratories), Vectastain ABC Elite kit and ImmPACT DAB substrate (all Vector Laboratories). Images were acquired in Leica MZ APO stereomicroscope with DC200 camera or Olympus SZX9 with DP72 camera. Fluorescence images were acquired in Zeiss Axioskop 2 microscope with objectives Ph3 Plan-Neofluar 40x/1.3 oil or Ph1 Plan-Neofluar 10x/0.3 and confocal Leica SP5. Bright-field light images were acquired in Nikon Diaphot 300 with objectives 4x/0.1 and 10x/0.25.
Dissected embryonic hearts were fixed overnight in 4 % PFA, washed in PBS and transferred into ScaleA2 reagent (4 M urea, 10 % glycerol, 0.1 % triton X-100) as described in . After two hours at RT hearts were photographed.
Alcian blue/Alizarin red staining
Embryos at E16.5-17.5 were dissected and scalded in hot water (65-70 °C, 2 min). They were dehydrated in 95 % ethanol for 48-72 h, changing solution every 12 h. After Alcian blue (Sigma) staining for 12 h, they were rinsed twice in ethanol and kept overnight. After clearing in 1 % KOH for 2 h and they were stained with Alizarin red (Sigma) for 5 h. Further clearing in 2 % KOH was carried out overnight, then in Glycerol (25 %) and 2 % KOH (75 %) for 8 h and Glycerol (50 %) and 2 % KOH (50 %) for 48 h. Tissue sections were rehydrydated and stained in 0.04 % Alcian solution for 10 min. Pictures were obtained using binocular microscope Olympus SYX9 and camera Olympus DP72.
Whole-mount in situ hybridization
Riboprobes: Mouse Foxd3 was cloned into pGEM-T-easy vector (Promega) using primers F-GGACCGCAAGAGTTCGCGGA, R-TCCGGAGCTCCCGTGTCGTT and antisense mRNA was transcribed with T7 polymerase. Mouse Sox9 gene was cloned into pGEM-T-easy using primers F-GAGCACTCTGGGCAATCTCAG, R-CTCAGGGTCTGGTGAGCTGTG and antisense mRNA was transcribed with T7 polymerase. Whole-mount in situ hybridization was performed using standard protocols.
We present a pioneering functional description of Meis2, a member of TALE-class homeodomain transcription factors, which is strongly expressed in cranial neural crest cells. We generated a conditional allele of the Meis2 gene. Using systemic and neural crest-specific inactivation of Meis2, we provide evidence that Meis2 is an important player in the regulatory network controlling cranial and cardiac neural crest cells.
double outlet right ventricle
neural crest cells
persistent truncus arteriosus
The work was supported by the Norwegian Research Council (grant #174938) (OM, SK) and the Grant Agency of the Czech Republic (P305/12/2042) (OM, JM) and LK11214 (OM, JM) from the Ministry of Education, Youth and Sports of the Czech Republic. We are grateful to A. Buchberg (Thomas Jefferson University, Philadelphia, USA) for anti-Meis2.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Bronner ME, LeDouarin NM. Development and evolution of the neural crest: an overview. Dev Biol. 2012;366(1):2–9.PubMed CentralView ArticlePubMedGoogle Scholar
- Dupin E, Sommer L. Neural crest progenitors and stem cells: from early development to adulthood. Dev Biol. 2012;366(1):83–95.View ArticlePubMedGoogle Scholar
- Sauka-Spengler T, Bronner-Fraser M. A gene regulatory network orchestrates neural crest formation. Nat Rev Mol Cell Biol. 2008;9(7):557–68.View ArticlePubMedGoogle Scholar
- Stuhlmiller TJ, Garcia-Castro MI. Current perspectives of the signaling pathways directing neural crest induction. Cell Mol Life Sci. 2012;69(22):3715–37.PubMed CentralView ArticlePubMedGoogle Scholar
- Minoux M, Rijli FM. Molecular mechanisms of cranial neural crest cell migration and patterning in craniofacial development. Development. 2010;137(16):2605–21.View ArticlePubMedGoogle Scholar
- Santagati F, Rijli FM. Cranial neural crest and the building of the vertebrate head. Nat Rev Neurosci. 2003;4(10):806–18.View ArticlePubMedGoogle Scholar
- Kirby ML, Hutson MR. Factors controlling cardiac neural crest cell migration. Cell Adh Migr. 2010;4(4):609–21.PubMed CentralView ArticlePubMedGoogle Scholar
- Lee RT, Nagai H, Nakaya Y, Sheng G, Trainor PA, Weston JA, et al. Cell delamination in the mesencephalic neural fold and its implication for the origin of ectomesenchyme. Development. 2013;140(24):4890–902.PubMed CentralView ArticlePubMedGoogle Scholar
- Nakamura T, Jenkins NA, Copeland NG. Identification of a new family of Pbx-related homeobox genes. Oncogene. 1996;13(10):2235–42.PubMedGoogle Scholar
- Jacobs Y, Schnabel CA, Cleary ML. Trimeric association of Hox and TALE homeodomain proteins mediates Hoxb2 hindbrain enhancer activity. Mol Cell Biol. 1999;19(7):5134–42.PubMed CentralView ArticlePubMedGoogle Scholar
- Shanmugam K, Green NC, Rambaldi I, Saragovi HU, Featherstone MS. PBX and MEIS as non-DNA-binding partners in trimeric complexes with HOX proteins. Mol Cell Biol. 1999;19(11):7577–88.PubMed CentralView ArticlePubMedGoogle Scholar
- Knoepfler PS, Bergstrom DA, Uetsuki T, Dac-Korytko I, Sun YH, Wright WE, et al. A conserved motif N-terminal to the DNA-binding domains of myogenic bHLH transcription factors mediates cooperative DNA binding with pbx-Meis1/Prep1. Nucleic Acids Res. 1999;27(18):3752–61.PubMed CentralView ArticlePubMedGoogle Scholar
- Mercader N, Leonardo E, Azpiazu N, Serrano A, Morata G, Martinez C, et al. Conserved regulation of proximodistal limb axis development by Meis1/Hth. Nature. 1999;402(6760):425–29.View ArticlePubMedGoogle Scholar
- Capdevila J, Tsukui T, Rodriquez EC, Zappavigna V, Izpisua Belmonte JC. Control of vertebrate limb outgrowth by the proximal factor Meis2 and distal antagonism of BMPs by Gremlin. Mol Cell. 1999;4(5):839–49.View ArticlePubMedGoogle Scholar
- Stankunas K, Shang C, Twu KY, Kao SC, Jenkins NA, Copeland NG, et al. Pbx/Meis deficiencies demonstrate multigenetic origins of congenital heart disease. Circ Res. 2008;103(7):702–09.PubMed CentralView ArticlePubMedGoogle Scholar
- Paige SL, Thomas S, Stoick-Cooper CL, Wang H, Maves L, Sandstrom R, et al. A temporal chromatin signature in human embryonic stem cells identifies regulators of cardiac development. Cell. 2012;151(1):221–32.PubMed CentralView ArticlePubMedGoogle Scholar
- Zhang X, Friedman A, Heaney S, Purcell P, Maas RL. Meis homeoproteins directly regulate Pax6 during vertebrate lens morphogenesis. Genes Dev. 2002;16(16):2097–107.PubMed CentralView ArticlePubMedGoogle Scholar
- Zhang X, Rowan S, Yue Y, Heaney S, Pan Y, Brendolan A, et al. Pax6 is regulated by Meis and Pbx homeoproteins during pancreatic development. Dev Biol. 2006;300(2):748–57.View ArticlePubMedGoogle Scholar
- Choe SK, Vlachakis N, Sagerstrom CG. Meis family proteins are required for hindbrain development in the zebrafish. Development. 2002;129(3):585–95.PubMedGoogle Scholar
- Vlachakis N, Choe SK, Sagerstrom CG. Meis3 synergizes with Pbx4 and Hoxb1b in promoting hindbrain fates in the zebrafish. Development. 2001;128(8):1299–312.PubMedGoogle Scholar
- Waskiewicz AJ, Rikhof HA, Hernandez RE, Moens CB. Zebrafish Meis functions to stabilize Pbx proteins and regulate hindbrain patterning. Development. 2001;128(21):4139–51.PubMedGoogle Scholar
- Agoston Z, Schulte D. Meis2 competes with the Groucho co-repressor Tle4 for binding to Otx2 and specifies tectal fate without induction of a secondary midbrain-hindbrain boundary organizer. Development. 2009;136(19):3311–22.View ArticlePubMedGoogle Scholar
- Choe SK, Lu P, Nakamura M, Lee J, Sagerstrom CG. Meis cofactors control HDAC and CBP accessibility at Hox-regulated promoters during zebrafish embryogenesis. Dev Cell. 2009;17(4):561–67.PubMed CentralView ArticlePubMedGoogle Scholar
- Ladam F, Sagerstrom CG. Hox regulation of transcription: more complex(es). Dev Dyn. 2014;243(1):4–15.View ArticlePubMedGoogle Scholar
- Azcoitia V, Aracil M, Martinez A, Torres M. The homeodomain protein Meis1 is essential for definitive hematopoiesis and vascular patterning in the mouse embryo. Dev Biol. 2005;280(2):307–20.View ArticlePubMedGoogle Scholar
- Hisa T, Spence SE, Rachel RA, Fujita M, Nakamura T, Ward JM, et al. Hematopoietic, angiogenic and eye defects in Meis1 mutant animals. EMBO J. 2004;23(2):450–59.PubMed CentralView ArticlePubMedGoogle Scholar
- Heine P, Dohle E, Bumsted-O'Brien K, Engelkamp D, Schulte D. Evidence for an evolutionary conserved role of homothorax/Meis1/2 during vertebrate retina development. Development. 2008;135(5):805–11.View ArticlePubMedGoogle Scholar
- Melvin VS, Feng W, Hernandez-Lagunas L, Artinger KB, Williams T. A morpholino-based screen to identify novel genes involved in craniofacial morphogenesis. Dev Dyn. 2013;242(7):817–31.PubMed CentralView ArticlePubMedGoogle Scholar
- DeLaughter DM, Christodoulou DC, Robinson JY, Seidman CE, Baldwin HS, Seidman JG, et al. Spatial transcriptional profile of the chick and mouse endocardial cushions identify novel regulators of endocardial EMT in vitro. J Mol Cell Cardiol. 2013;59:196–204.PubMed CentralView ArticlePubMedGoogle Scholar
- Erdogan F, Ullmann R, Chen W, Schubert M, Adolph S, Hultschig C, et al. Characterization of a 5.3 Mb deletion in 15q14 by comparative genomic hybridization using a whole genome “tiling path” BAC array in a girl with heart defect, cleft palate, and developmental delay. Am J Med Genet A. 2007;143(2):172–78.View ArticleGoogle Scholar
- Johansson S, Berland S, Gradek GA, Bongers E, de LN, Pfundt R, et al. Haploinsufficiency of MEIS2 is associated with orofacial clefting and learning disability. Am J Med Genet A. 2014;164A(7):1622–6.View ArticlePubMedGoogle Scholar
- Crowley MA, Conlin LK, Zackai EH, Deardorff MA, Thiel BD, Spinner NB. Further evidence for the possible role of MEIS2 in the development of cleft palate and cardiac septum. Am J Med Genet A. 2010;152A(5):1326–27.View ArticlePubMedGoogle Scholar
- Louw JJ, Corveleyn A, Jia Y, Hens G, Gewillig M, Devriendt K. MEIS2 involvement in cardiac development, cleft palate, and intellectual disability. Am J Med Genet A. 2015;167A(5):1142–6.View ArticlePubMedGoogle Scholar
- Cai M, Langer EM, Gill JG, Satpathy AT, Albring JC, KC W, et al. Dual actions of Meis1 inhibit erythroid progenitor development and sustain general hematopoietic cell proliferation. Blood. 2012;120(2):335–46.PubMed CentralView ArticlePubMedGoogle Scholar
- Rinon A, Lazar S, Marshall H, Buchmann-Moller S, Neufeld A, Elhanany-Tamir H, et al. Cranial neural crest cells regulate head muscle patterning and differentiation during vertebrate embryogenesis. Development. 2007;134(17):3065–75.View ArticlePubMedGoogle Scholar
- Schorle H, Meier P, Buchert M, Jaenisch R, Mitchell PJ. Transcription factor AP-2 essential for cranial closure and craniofacial development. Nature. 1996;381(6579):235–38.View ArticlePubMedGoogle Scholar
- Zhang J, Hagopian-Donaldson S, Serbedzija G, Elsemore J, Plehn-Dujowich D, McMahon AP, et al. Neural tube, skeletal and body wall defects in mice lacking transcription factor AP-2. Nature. 1996;381(6579):238–41.View ArticlePubMedGoogle Scholar
- Cecconi F, Proetzel G, varez-Bolado G, Jay D, Gruss P. Expression of Meis2, a Knotted-related murine homeobox gene, indicates a role in the differentiation of the forebrain and the somitic mesoderm. Dev Dyn. 1997;210(2):184–90.View ArticlePubMedGoogle Scholar
- Macatee TL, Hammond BP, Arenkiel BR, Francis L, Frank DU, Moon AM. Ablation of specific expression domains reveals discrete functions of ectoderm- and endoderm-derived FGF8 during cardiovascular and pharyngeal development. Development. 2003;130(25):6361–74.PubMed CentralView ArticlePubMedGoogle Scholar
- Soriano P. Generalized lacZ expression with the ROSA26 Cre reporter strain. Nat Genet. 1999;21(1):70–1.View ArticlePubMedGoogle Scholar
- Hatou S, Yoshida S, Higa K, Miyashita H, Inagaki E, Okano H, et al. Functional corneal endothelium derived from corneal stroma stem cells of neural crest origin by retinoic acid and Wnt/beta-catenin signaling. Stem Cells Dev. 2013;22(5):828–39.View ArticlePubMedGoogle Scholar
- Yoshida S, Shimmura S, Nagoshi N, Fukuda K, Matsuzaki Y, Okano H, et al. Isolation of multipotent neural crest-derived stem cells from the adult mouse cornea. Stem Cells. 2006;24(12):2714–22.View ArticlePubMedGoogle Scholar
- Ittner LM, Wurdak H, Schwerdtfeger K, Kunz T, Ille F, Leveen P, et al. Compound developmental eye disorders following inactivation of TGFbeta signaling in neural-crest stem cells. J Biol. 2005;4(3):11.PubMed CentralView ArticlePubMedGoogle Scholar
- Olaopa M, Zhou HM, Snider P, Wang J, Schwartz RJ, Moon AM, et al. Pax3 is essential for normal cardiac neural crest morphogenesis but is not required during migration nor outflow tract septation. Dev Biol. 2011;356(2):308–22.PubMed CentralView ArticlePubMedGoogle Scholar
- Chang CP, Stankunas K, Shang C, Kao SC, Twu KY, Cleary ML. Pbx1 functions in distinct regulatory networks to pattern the great arteries and cardiac outflow tract. Development. 2008;135(21):3577–86.PubMed CentralView ArticlePubMedGoogle Scholar
- Mundell NA, Labosky PA. Neural crest stem cell multipotency requires Foxd3 to maintain neural potential and repress mesenchymal fates. Development. 2011;138(4):641–52.PubMed CentralView ArticlePubMedGoogle Scholar
- Mori-Akiyama Y, Akiyama H, Rowitch DH, de CB. Sox9 is required for determination of the chondrogenic cell lineage in the cranial neural crest. Proc Natl Acad Sci U S A. 2003;100(16):9360–65.PubMed CentralView ArticlePubMedGoogle Scholar
- Bai Y, Wang J, Morikawa Y, Bonilla-Claudio M, Klysik E, Martin JF. Bmp signaling represses Vegfa to promote outflow tract cushion development. Development. 2013;140(16):3395–402.PubMed CentralView ArticlePubMedGoogle Scholar
- Hama H, Kurokawa H, Kawano H, Ando R, Shimogori T, Noda H, et al. Scale: a chemical approach for fluorescence imaging and reconstruction of transparent mouse brain. Nat Neurosci. 2011;14(11):1481–88.View ArticlePubMedGoogle Scholar