Figure 4

In situ hybridizations of selected intergenic transcripts. The charts show relative amounts of transcripts as measured by qPCR at E11.5 (green), E13.5 (blue) or E15.5 (red). Expression levels at day E11.5 are normalized to 1. Correlation coefficients (R²) indicate the relative correlations between the expression of both the protein coding genes and the associated intergenic transcripts. Tiling array data (scales in log₂ on Y-axes) and genomic maps are also shown. A. Lmx1b gene and associated upstream region, with bidirectional transcripts annotated here as Lmx1b and C130021l20Rik. A potential alternative start site for Lmx1b, 60 kb upstream (AK020435) shows the same expression specificity. B. Bidirectional transcription at the Hand2 locus, with both Hand2 and the AK078510 transcript displaying related patterns in the posterior margin of developing forelimbs. C. An as yet unknown intergenic transcript (BC025054) located 50 kb downstream of the Sox4 locus, on the same strand of chromosome 13, which is expressed like Sox4, suggesting it may be a remote 3' exon of this gene. D: Bidirectional transcription at the Prdm16 locus on chromosome 4, with an as yet unknown transcript mimicking Prdm16 expression in the E12.5 digital plate.