Mori S, Nishikawa S I, Yokota Y
Department of Molecular Genetics, Kyoto University Graduate School of Medicine, Shogoin Kawahara-cho 53, Sakyo-ku, Kyoto 606-8507, Japan.
EMBO J. 2000 Nov 1;19(21):5772-81. doi: 10.1093/emboj/19.21.5772.
Id proteins are thought to be negative regulators of cell differentiation and positive regulators of cell proliferation. Mammary glands of Id2(-/-) female mice reveal severely impaired lobulo-alveolar development during pregnancy. Id2(-/-) mammary epithelia show no precocious maturation, but instead exhibit intrinsic defects in both cell proliferation and cell survival, implying that the role of Id2 in pregnant mammary epithelia is mainly stimulation of cell proliferation and support of cell viability. Expression studies of genes required for mammary gland development suggest Id2 to be a downstream or parallel factor of these genes. A decrease in the DNA binding activity of Stat5 was also observed in Id2(-/-) mammary glands at 7 days post-coitus. Our results indicate an indispensable role of Id2 in pregnant mammary glands.
Id蛋白被认为是细胞分化的负调节因子和细胞增殖的正调节因子。Id2基因敲除雌性小鼠的乳腺在怀孕期间显示出小叶-腺泡发育严重受损。Id2基因敲除的乳腺上皮没有早熟成熟，而是在细胞增殖和细胞存活方面都表现出内在缺陷，这意味着Id2在妊娠乳腺上皮中的作用主要是刺激细胞增殖和维持细胞活力。乳腺发育所需基因的表达研究表明Id2是这些基因的下游或平行因子。在交配后7天的Id2基因敲除乳腺中也观察到Stat5的DNA结合活性降低。我们的结果表明Id2在妊娠乳腺中具有不可或缺的作用。
