Don J, Winer M A, Wolgemuth D J
Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Mol Reprod Dev. 1994 May;38(1):16-23. doi: 10.1002/mrd.1080380104.
Previous studies have shown that in adult male mice, expression of the meg1 gene is restricted to meiotic and early postmeiotic testicular germ cells. We have now analyzed the expression of meg1 during postnatal testicular development and the comparable meiotic stages in the female. The 0.75 kb transcript for meg1 begins to accumulate in testes at d8-9 of postnatal (pn) development, coincident with the entry of germ cells into meiosis, and is expressed most abundantly at pn d14 and subsequent stages, when the spermatocytes have entered pachytene. In situ hybridization analysis shows that meg1 is expressed at very low levels in leptotene cells and increases as the cells progress through zygotene and pachytene stages. In the embryonic ovary, meg1 is not detected until after day 15 of gestation when the cells have entered the pachytene stage of meiosis I. In situ hybridization analysis suggests that meg1 transcripts are expressed at higher levels in degenerating rather than in healthy pachytene stage oocytes; meg1 is not expressed in any cells of the adult ovary, regardless of the stage of follicular development. These results suggest that meg1 is indeed a meiosis-associated gene in both male and female germ cells through the pachytene stage of meiosis I and appears to exhibit sex-specific differences in its expression thereafter.
以往的研究表明，在成年雄性小鼠中，meg1基因的表达仅限于减数分裂期和减数分裂后早期的睾丸生殖细胞。我们现在分析了meg1在出生后睾丸发育过程中的表达情况以及雌性小鼠中类似的减数分裂阶段。meg1的0.75 kb转录本在出生后（pn）发育的第8 - 9天开始在睾丸中积累，这与生殖细胞进入减数分裂的时间一致，并且在pn d14及后续阶段表达最为丰富，此时精母细胞已进入粗线期。原位杂交分析表明，meg1在细线期细胞中的表达水平非常低，并随着细胞进入偶线期和粗线期而增加。在胚胎卵巢中，直到妊娠第15天细胞进入减数分裂I的粗线期后才检测到meg1。原位杂交分析表明，meg1转录本在退化的粗线期卵母细胞中表达水平较高，而在健康的粗线期卵母细胞中表达水平较低；无论卵泡发育处于哪个阶段，meg1在成年卵巢的任何细胞中均不表达。这些结果表明，meg1在雄性和雌性生殖细胞中确实是一个与减数分裂相关的基因，直至减数分裂I的粗线期，此后其表达似乎表现出性别特异性差异。
