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Mediation of Growth Hormone-dependent Transcriptional Activation by Mammary Gland Factor/Stat 5
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.
https://hal-univ-tours.archives-ouvertes.fr/hal-02427585
Contributor : Fabrice Gouilleux <>
Submitted on : Friday, January 3, 2020 - 5:42:26 PM
Last modification on : Monday, January 6, 2020 - 4:27:09 PM
Contributor : Fabrice Gouilleux <>
Submitted on : Friday, January 3, 2020 - 5:42:26 PM
Last modification on : Monday, January 6, 2020 - 4:27:09 PM
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