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Expression of milk protein genes is induced directly by exogenous STAT5 without prolactin‐mediated signal transduction in transgenic mice
Author(s) -
Inuzuka Hiroyuki,
Yamanouchi Keitaro,
Tachi Chikashi,
Tojo Hideaki
Publication year - 1999
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199910)54:2<121::aid-mrd3>3.0.co;2-t
Subject(s) - stat5 , biology , transgene , signal transduction , genetically modified mouse , prolactin , gene , microbiology and biotechnology , gene expression , stat protein , endogeny , endocrinology , stat3 , genetics , hormone
STAT5 is a member of the family of STAT (signal transducer for activating transcription), which was isolated from nuclear extracts of the lactating gland of sheep. It was reported that, in vitro, STAT5 could be activated directly by prolactin (PRL) without PRL‐mediated signal transduction. The present study was conducted to investigate above the possibility in vivo, using the transgenic mice overexpressing ovine STAT5 (oSTAT5) under the control of MMTV promoter. Three transgenic mouse lines that expressed the exogenously introduced oSTAT5 in their mammary glands were established. The expression levels of exogenous oSTAT5 were higher than those of endogenous STAT in the mammary glands of all of the three transgenic lines. Although the expression levels of endogenous milk protein genes, WAP, and β‐casein genes, were not correlated with oSTAT5 expression, the expression levels of WAP and β‐casein were induced by exogenous oSTAT5 in the transgenic mice. The present study demonstrated, at very least, that STAT5 expression can directly activate the expression of milk protein genes, and particularly the WAP gene without PRL‐mediated signal transduction. Mol. Reprod. Dev. 54:121–125, 1999. © 1999 Wiley‐Liss, Inc.