title: Spleen tyrosine kinase regulates mammary epithelial cell proliferation in mammary glands of dairy cows.
abstract: Spleen tyrosine kinase (SYK) is a nonreceptor tyrosine kinase that has been considered a hematopoietic cell-specific signal transducer involved in cell proliferation and differentiation. However, the role of SYK in normal mammary gland is still poorly understood. Here we show that SYK is expressed in mammary glands of dairy cows. Expression of SYK was higher in dry period mammary tissues than in lactating mammary tissues. Knockdown and overexpression of SYK affected dairy cow mammary epithelial cell proliferation as well as the expression of signal molecules involved in proliferation, including protein kinase B (PKB, also known as AKT1), p42/44 mitogen-activated protein kinase (MAPK), and signal transducer and activator of transcription 5 (STAT5). Dual-luciferase reporter assay showed that SYK increased the transcriptional activity of the AKT1 promoter, and cis-elements within the AKT1 promoter region from -439 to -84 bp mediated this regulation. These results suggest that SYK affects mammary epithelial cell proliferation by activating AKT1 at the transcriptional level in mammary glands of dairy cows, which is important for the mammary remodeling process in dry cows as well as for increasing persistency of lactation in lactating cows.
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Hou
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Weinan
authors.initials: W
authors.lastname: Xing
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Duan
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Qingzhang
authors.initials: Q
authors.lastname: Li
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Gao
authors.affiliation: College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China. Electronic address: linlu516@163.com.
authors.forename: Ye
authors.initials: Y
authors.lastname: Lin
mesh_terms: D000818:Animals; D002417:Cattle; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism*; D000072377:Syk Kinase
chemical_list: D000072377:Syk Kinase
keywords: AKT1; SYK; mammary gland; proliferation