A: Schematic view of the organization of the murine Mtss1 gene based on Ensemble entry ENSMUSG00000022353. The 5' and 3' UTRs (dark boxes) are not drawn to scale, nor are the intronic regions. Comparison of the murine gene with that of the rat (ENSRNOG00000009001; transcript ENSRNOT00000023505) further suggests that the region labeled here as exon 15 may contain an additional, 108 bp long intron (I, marked in light gray) which would result in the division of exon 15 into two exons of 354 and 239 bps, respectively. Also, the length of exon 14 may either encompass 163 (ENSMUST00000080371) or 208 bp (ENSMUST00000036782). The 45 bps in question are located C-terminal and alternatively form part of the intron separating exons 14 and 15. Regions covered by the in situ hybridization probes used are labeled by horizontal lines A and B. Arrows mark positions of primers used (black arrows, forward primers; open arrows, reverse primers). B: Schematic view of the derived protein. The N-terminal IMD domain and the C-terminal WH2 domain are shown as gray boxes. The localization of the putative nuclear import (I) and export (E) motives are indicated as black and white boxes, respectively. C, D: Expression of Mtss1 splice variants in the early postnatal and adult murine cerebellum. Use of primers located in exons 7 and 13 (primers 2, 5; panel C) reveals the existence of 4 splice variants (the band representing exon combination 11/12/12a/13 reproduces only very weakly here) in the developing and adult cerebellum, as does the use of primers located in exons 11 and 13 (primers 4, 5; panel D). Note that the relative intensity in particular of the band representing splice variants comprising exons 11/12/13 and 11/12a/13 varies during development. The band labeled gapdh is a loading control. Numbers indicate days postnatal; Ad, adult. The arrow indicates a spurious amplificate from an unrelated sequence: This was verified by sequencing, as were the products labeled as bands 11/12/12a/13, 11/12/13, 11/12a/13 and 11/13.