The organisation of the mouse secretogranin II gene.

We have characterized the gene which encodes mouse secretogranin II (previously also referred to as chromogranin C), a tyrosine-sulfated secretory protein belonging to the granin (chromogranin/secretogranin) family which is found in secretory granules of most endocrine cells and neurons. The secretogranin II gene was found to contain 2 exons. In contrast to chromogranin A and chromogranin B, the two previously characterized granin genes, the entire secretogranin II protein is encoded by a single exon, exon 2, with exon 1 containing only a 5'-untranslated sequence. Consistent with previous data on the expression of secretogranin II, the putative promoter region was found to contain a cAMP-responsive element and a potential AP-1 binding site.     

Complex structure and regulation of expression of the rat gene for inward rectifier potassium channel Kir7.1

Genomic organization of the rat inward rectifier K(+) channel Kir7.1 was determined in an attempt to clarify how multiple species of its mRNA are generated in a tissue-specific manner and how its expression is regulated. The rat Kir7.1 gene spans >40 kilobases (kb) and consists of eight exons; the first four exons encode the 5'-untranslated region that is unusually long ( approximately 3 kb). The coding region is located in exons 5 and 6. In the testis, exon 4 is processed as four exons (4a-4d), whereas it is recognized as a single exon in the small intestine. The three major species of rat Kir7.1 mRNA (1.4, 2.2, and 3.2 kb) were found to arise from alternative usage of the two promoters and polyadenylation signals and by alternative splicing of the 5'-noncoding exons. The splicing pattern of the 5'-noncoding exons is quite complex and highly tissue-specific, suggesting that complex mechanisms may operate to regulate the Kir7.1 expression. Deletion and mutational analysis of the promoter activity indicated that the rat Kir7.1 gene is regulated by cAMP through a CCAAT element. The cAMP induction was also demonstrated using the rat follicular cell line FRTL-5 endogenously expressing Kir7.1.