Cooperativity of sequence elements mediates tissue specificity of the rat insulin II gene.
The 5'-flanking region of the rat insulin II gene (-448 to +50) is sufficient for tissue-specific expression. To further determine the tissue-specific cis-acting element(s), important sequences defined by linker-scanning mutagenesis were placed upstream of a heterologous promoter and transfected into insulin-producing and -nonproducing cells. Rat insulin promoter element 3 (RIPE3), which spans from -125 to -86, was shown to confer beta-cell-specific expression in either orientation. However, two subregions of RIPE3, RIPE3a and RIPE3b (defined by linker-scanning mutations), displayed only marginal activities. These results suggest that the two subregions cooperate to confer tissue specificity, presumably via their cognate binding factors.
Hwung
Y P
YP
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Gu
Y Z
YZ
Tsai
M J
MJ
D000818:Animals; D002460:Cell Line; D002645:Chickens; D005786:Gene Expression Regulation; D005796:Genes; D005809:Genes, Regulator; D007328:Insulin / Q000235:genetics*; D009710:Nucleotide Mapping; D015345:Oligonucleotide Probes; D010047:Ovalbumin / Q000235:genetics; D011401:Promoter Regions, Genetic; D051381:Rats; D012260:Ribonucleases
D007328:Insulin; D015345:Oligonucleotide Probes; D010047:Ovalbumin; D012260:Ribonucleases