Expression of thyroid transcription factor 1 gene can be regulated at the transcriptional and posttranscriptional levels.
The complete structure of the gene for thyroid transcription factor 1 (TTF-1), both in rats and humans, has been determined. The rat TTF-1 gene shows three transcriptional start sites and contains two introns, one of which is alternatively spliced. Nuclear run-on and transient transfection experiments indicate that TTF-1 gene expression can be controlled at different levels. Using thyroid and nonthyroid cell lines, it can be shown that transcriptional mechanisms are involved in controlling thyroid-specific expression of the TTF-1 gene. In contrast, in thyroid cells expressing an activated Ki-ras oncogene, the steady-state level of TTF-1 mRNA is greatly reduced, while transcription of the TTF-1 gene is only moderately affected, suggesting that the accumulation of TTF-1 mRNA can be regulated by a posttranscriptional, Ras-sensitive mechanism.
Lonigro
R
R
Department of Science and Biomedical Technology, University of Udine, Italy.
De Felice
M
M
Biffali
E
E
Macchia
P E
PE
Damante
G
G
Asteria
C
C
Di Lauro
R
R
D000818:Animals; D001483:Base Sequence; D002461:Cell Line, Transformed / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D011905:Genes, ras / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013961:Thyroid Gland / Q000166:cytology; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D017931:DNA Primers; D018398:Homeodomain Proteins; C000614412:NKX2-1 protein, human; C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D012333:RNA, Messenger; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors