Mediation of growth hormone-dependent transcriptional activation by mammary gland factor/Stat 5.
J Biol Chem
; 270(16): 9448-53, 1995 Apr 21.
Article
em En
| MEDLINE
| ID: mdl-7721871
ABSTRACT
Previous observations have shown that binding of growth hormone to its receptor leads to activation of transcription factors via a mechanism involving phosphorylation on tyrosine residues. In order to establish whether the prolactin-activated transcription factor Stat 5 (mammary gland factor) is also activated by growth hormone, nuclear extracts were prepared from COS-7 cells transiently expressing transfected Stat 5 and growth hormone receptor cDNA. Gel electrophoresis mobility shift analyses revealed the growth hormone-dependent presence of specific DNA-binding proteins in these extracts. The complexes formed could be supershifted by polyclonal anti-Stat 5 antiserum. In other experiments nuclear extracts from growth hormone-treated Chinese hamster ovary cells stably expressing transfected growth hormone receptor cDNA and liver from growth hormone-treated hypophysectomized rats were used for gel electrophoresis mobility shift analyses. These also revealed the presence of specific DNA-binding proteins sharing antigenic determinants with Stat 5. Stat 5 cDNA was shown to be capable of complementing the growth hormone-dependent activation of transcription of a reporter gene in the otherwise unresponsive COS-7 cell line. This complementation was dependent on the presence of Stat 5 tyrosine 694, suggesting a role for phosphorylation of this residue in growth hormone-dependent activation of DNA-binding and transcription.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Hormônio do Crescimento
/
Ativação Transcricional
/
Transativadores
/
Proteínas de Ligação a DNA
/
Proteínas do Leite
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1995
Tipo de documento:
Article