Lopez Pascal, Yaman Ruken, Lopez-Fernandez Luis A, Vidal Frédérique, Puel Daniel, Clertant Philippe, Cuzin François, Rassoulzadegan Minoo
University of Nice, INSERM U470, 06108 Nice, France.
J Biol Chem. 2003 Jan 17;278(3):1751-7. doi: 10.1074/jbc.M207434200. Epub 2002 Nov 6.
We identified a new member of the phosducin-like (PhLP) protein family that is predominantly, if not exclusively, expressed in male and female germ cells. In situ analysis on testis sections and analysis of purified spermatogenic cell fractions evidenced a stage-specific expression with high levels of RNA and protein in pachytene spermatocytes and round spermatids. Three mRNA species were detected, which correspond to different polyadenylation sites and vary in abundance during germ cell maturation. Only low levels of RNA were detected in whole ovary extracts, but expression of the protein became detectable within hours after hormonal induction of superovulation. The gene (Mgcphlp) is located on mouse chromosome 5 in the immediate vicinity of the Clock locus. The predicted amino acid sequence shows extensive similarities not only with the known mammalian PhLP proteins but also with the yeast phosducin-like protein Plp2, required for the production and growth of haploid cells. Expression of the murine protein was found to complement the defect of a yeast plp2 Delta mutant. We propose that MgcPhLP/Plp2 proteins exert a function in germ cell maturation that is conserved from yeast to mammals.
我们鉴定出一种类磷光蛋白（PhLP）家族的新成员，该成员主要（若不是唯一）在雄性和雌性生殖细胞中表达。对睾丸切片的原位分析以及对纯化的生精细胞组分的分析表明，其表达具有阶段特异性，在粗线期精母细胞和圆形精子细胞中RNA和蛋白质水平较高。检测到三种mRNA，它们对应于不同的聚腺苷酸化位点，并且在生殖细胞成熟过程中丰度有所不同。在整个卵巢提取物中仅检测到低水平的RNA，但在激素诱导超排卵后的数小时内即可检测到该蛋白的表达。该基因（Mgcphlp）位于小鼠5号染色体上，紧邻Clock基因座。预测的氨基酸序列不仅与已知的哺乳动物PhLP蛋白具有广泛的相似性，而且与单倍体细胞产生和生长所需的酵母类磷光蛋白Plp2也具有广泛的相似性。发现小鼠蛋白的表达能够弥补酵母plp2 Delta突变体的缺陷。我们提出，MgcPhLP/Plp2蛋白在生殖细胞成熟过程中发挥作用，这种作用从酵母到哺乳动物都是保守的。
