scholarly journals Transforming growth factor β induction of insulin gene expression is mediated by pancreatic and duodenal homeobox gene-1 in rat insulinoma cells

2000 ◽  
Vol 267 (4) ◽  
pp. 971-978 ◽  
Author(s):  
Yoshitaka Sayo ◽  
Hitoshi Hosokawa ◽  
Hitomi Imachi ◽  
Koji Murao ◽  
Makoto Sato ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Homeobox Gene ◽  
Transforming Growth Factor Β ◽  
Insulin Gene ◽  
Insulin Gene Expression ◽  
Insulinoma Cells ◽  
Rat Insulinoma

scholarly journals Transforming growth factor β-1 enhances Smad transcriptional activity through activation of p8 gene expression

2001 ◽  
Vol 357 (1) ◽  
pp. 249 ◽  
Author(s):  
Andrés C. GARCÍA-MONTERO ◽  
Sophie VASSEUR ◽  
Luciana E. GIONO ◽  
Eduardo CANEPA ◽  
Silvia MORENO ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factor ◽  
Transcriptional Activity ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β

Extinction of insulin gene expression in hybrids between beta cells and fibroblasts is accompanied by loss of the putative beta-cell-specific transcription factor IEF1

1991 ◽  
Vol 11 (3) ◽  
pp. 1547-1552
Author(s):  
D Leshkowitz ◽  
M D Walker
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Activity ◽  
Insulin Gene ◽  
Hybrid Cells ◽  
Dna Binding Activity ◽  
Insulin Producing Cells ◽  
Insulin Gene Expression ◽  
Insulinoma Cells

Insulin-producing cells and fibroblasts were fused to produce hybrid lines. In hybrids derived from both hamster and rat insulinoma cells, no insulin mRNA could be detected in any of seven lines examined by Northern (RNA) analysis despite the presence in each line of the insulin genes of both parental cells. Hybrid cells were transfected with recombinant chloramphenicol acetyltransferase plasmids containing defined segments of the rat insulin I gene 5' flank. We observed no transcriptional activity of the intact insulin enhancer or of IEB2, a critical cis-acting element of the insulin enhancer. IEB2 has previously been shown to interact in vitro with IEF1, a DNA-binding activity observed selectively in insulin-producing cells. Hybrid cells showed no detectable IEF1 activity. Furthermore, the insulin enhancer was unable to reduce transcription directed by the Moloney sarcoma virus enhancer in a double-enhancer construct. Thus, extinction of insulin gene expression in the hybrids apparently does not operate through a direct action of repressors on the insulin enhancer; rather, extinction is accompanied by, and may be caused by, reduced DNA-binding activity of the putative transcriptional activator IEF1.

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