Expression of rat thyrotropin-releasing hormone (TRH) gene in TRH-producing tissues of transgenic mice requires sequences located in exon 1.
Endocrinology
; 139(1): 252-9, 1998 Jan.
Article
em En
| MEDLINE
| ID: mdl-9421422
ABSTRACT
TRH, an amidated tripeptide secreted by certain hypothalamic neurons, is a principal regulator of TSH secretion and thyroid hormone release. TRH is also produced by other neurons in the central nervous system, where it appears to function as a neuromodulator or neurotransmitter, and by certain endocrine cells, where it may act as an autocrine or paracrine factor. The genomic organization of the rat TRH (rTRH) gene is well understood; however, the domains of the rTRH gene that regulate expression are less well characterized. We observed that the region between -47 and +6 of the rTRH gene (relative to the transcription start site at +1) was active in CA-77 cells, a medullary thyroid carcinoma cell line model of TRH production, but was not active in transgenic mice. Inclusion of most of exon 1 (84 out of 103 bp; -47 to +84) increased promoter activity in CA-77 cells and was active in transgenic mice, principally in tissues that normally express the TRH gene. Further lengthening of the 5' end to -243, -547, or -776 retained this expression in TRH-producing tissues in transgenic mice, while further increasing activity in CA-77 cells. These results suggest that cis element(s) located within exon 1 are necessary for the expression of the rTRH gene in vivo.
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Base de dados:
MEDLINE
Assunto principal:
Regulação da Expressão Gênica
/
Éxons
/
Hormônio Liberador de Tireotropina
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Endocrinology
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Estados Unidos