Analyses of the involvement of LTR-transposon in meiotic regulation of mammalian oocytes.

利用猪卵母细胞和巨噬细胞(MAEL)分析了哺乳动物基因组中被认为是寄生虫基因的LTR转座元件(Te)在哺乳动物卵母细胞减数分裂调控中的可能作用，发现Te在睾丸中参与了LtR-Te抑制因子piRNA的生物合成。从猪卵母细胞中克隆了猪MAEL基因，发现猪MAEL在卵母细胞和睾丸中的相对分子质量不同。在猪卵母细胞中，MAEL基因在整个减数分裂过程中都有表达，并且随着减数分裂的进行，MAEL蛋白逐渐减少。用MAEL mRNA或反义RNA注入卵母细胞，通过人工调控MAEL蛋白的表达来分析MAEL在减数分裂成熟中的作用。但对卵母细胞成熟过程中的微管组织和减数分裂进程无明显影响。因此，我不能提供证据表明Mael以及随后的Ltr-Te参与猪卵母细胞的减数分裂调控。

Possible involvement of LTR-transposable elements (Te), which are thought to be parasite genes in mammalian genom, in meiotic regulation of mammalian oocytes were analyzed using porcine oocytes and Maelstrom (MAEL), which was shown in testis to be involved in the biosynthesis of piRNA, an inhibitor of LTR-Te. Porcine MAEL cDNA was cloned from porcine oocytes and found that the molecular weights of porcine MAEL were different between oocyte and testis. In porcine oocytes, MAEL mRNA was present throughout meiosis and MAEL protein was decreased according with the progression of meiosis. MAEL functions on meiotic maturation were analyzed by artificial expression control of MAEL protein using MAEL mRNA or antisense RNA injection into oocytes. However, there were no effects on microtubule organization and meiotic progression during oocyte maturation. Therefore, I cannot provide the evidence showing the involvement of MAEL, and subsequently LTR-Te, in meiotic regulation of porcine oocytes.