Expression of aberrantly spliced Mitf-M transcripts at black patches of the black spotting mouse.

<p>The RT-PCR analysis was performed with the downstream reverse primer on exon 7 (Rp7). RNA was isolated from the skin of each mouse at the age of 30 days (P30). Exon 4 encodes an activation domain (AD). PCR products were detected as a single band with RNA from wild type mouse skin (WT). In two separate black patches from the black spotting mouse (P30), aberrantly spliced Mitf-M transcripts were detected in addition to authentic Mitf-M mRNA. The sizes of four major PCR products are 882 bp (product a), 778 bp (product b), 694 bp or 682 bp (product c), and 598 bp (product d). The product c contained two species of PCR products: the 694-bp band lacking exon 3 and the 682-bp band lacking exon 4. The predicted identity of the splicing products is shown at bottom: (a) Mitf-M mRNA containing a portion of LINE-1 (104-bp segment), (b) authentic Mitf-M mRNA, (c) Mitf-M mRNA lacking exon 3 or exon 4, and (d) Mitf-M mRNA lacking exon 3 and exon 4. The amplified region is shown in red.