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Genes Dev. 1997 Jan 15;11(2):179-86.

Stat5a is mandatory for adult mammary gland development and lactogenesis.

Author information

1
Laboratory of Biochemistry and Metabolism, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland 20892-1812, USA.

Abstract

Prolactin (PRL) induces mammary gland development (defined as mammopoiesis) and lactogenesis. Binding of PRL to its receptor leads to the phosphorylation and activation of STAT (signal transducers and activators of transcription) proteins, which in turn promote the expression of specific genes. The activity pattern of two STAT proteins, Stat5a and Stat5b, in mammary tissue during pregnancy suggests an active role for these transcription factors in epithelial cell differentiation and milk protein gene expression. To investigate the function of Stat5a in mammopoiesis and lactogenesis we disrupted this gene in mice by gene targeting. Stat5a-deficient mice developed normally and were indistinguishable from hemizygous and wild-type littermates in size, weight, and fertility. However, mammary lobuloalveolar outgrowth during pregnancy was curtailed, and females failed to lactate after parturition because of a failure of terminal differentiation. Although Stat5b has a 96% similarity with Stat5a and a superimposable expression pattern during mammary gland development it failed to counterbalance for the absence of Stat5a. These results document that Stat5a is the principal and an obligate mediator of mammopoietic and lactogenic signaling.

PMID:
9009201
DOI:
10.1101/gad.11.2.179
[Indexed for MEDLINE]
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