Dynamic expression of DNMT3a and DNMT3b isoforms during male germ cell development in the mouse
Dynamic expression of DNMT3a and DNMT3b isoforms during male germ cell development in the mouse
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DOI：
10.1016/j.ydbio.2006.04.436
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发表时间：
2006-08-01
影响因子：
2.7
通讯作者：
Trasler, Jacquetta M.
中科院分区：
文献类型：
--
作者：
La Salle, Sophie;Trasler, Jacquetta M.
在雄性生殖细胞系中，序列特异性甲基化模式最初是在出生前在二倍体生殖细胞中获得的，并在出生后精子发生期间进一步巩固。目前还不清楚DNA甲基转移酶如何参与生殖细胞中这些模式的建立和/或维持，或者它们的活性是如何调节的。我们比较了小鼠雄性生殖细胞中假定的从头DNA甲基转移酶DNMT 3a和DNMT 3b的时间表达模式。分离有丝分裂、减数分裂和减数分裂后的雄性生殖细胞，并使用定量RT-PCR和蛋白质印迹检测Dnmt 3a和Dnmt 3b的各种转录变体和同种型的表达。我们发现，增殖和分化的男性生殖细胞的特点是独特的表达谱。Dnmt 3a 2和Dmnt 3 B b转录在A型精原细胞中的表达水平最高，在B型精原细胞和前细线期精母细胞中显著降低，在细线期/偶线期精母细胞中再次升高，而Dnmt 3a表达除了在B型精原细胞中增加外，大部分是恒定的。在所有病例中，表达随着粗线的进展而下降。在蛋白水平上，DNMT 3a是B型精原细胞中的主要亚型，而DNMT 3a 2、DNMT 3 b 2和DNMT 3 b 3在除粗线期精母细胞外的大部分精子发生过程中表达。在圆形精子细胞中也检测到DNMT 3a 2和DNMT 3b 2。总之，这些数据突出了这些基因在精子发生过程中受到严格调控的表达，并提供了DNMT可能对男性生殖细胞中甲基化模式的建立和/或维持有差异的证据。(c)2006年爱思唯尔公司All rights reserved.
In the male germ line, sequence-specific methylation patterns are initially acquired prenatally in diploid gonocytes and are further consolidated after birth during spermatogenesis. It is still unclear how DNA methyltransferases are involved in establishing and/or maintaining these patterns in germ cells, or how their activity is regulated. We compared the temporal expression patterns of the postulated de novo DNA methyltransferases DNMT3a and DNMT3b in murine male germ cells. Mitotic, meiotic and post-meiotic male germ cells were isolated, and expression of various transcript variants and isoforms of Dnmt3a and Dnmt3b was examined using Quantitative RT-PCR and Western blotting. We found that proliferating and differentiating male germ cells were marked by distinctive expression profiles. Dnmt3a2 and Dmnt3b transcripts were at their highest levels in type A spermatogonia, decreased dramatically in type B spermatogonia and preleptotene spermatocytes and rose again in leptotene/zygotene spermatocytes, while Dnmt3a expression was mostly constant, except in type B spermatogonia where it increased. In all cases, expression declined as pachynema progressed. At the protein level, DNMT3a was the predominant isoform in type B spermatogonia, while DNMT3a2, DNMT3b2, and DNMT3b3 were expressed throughout most of spermatogenesis, except in pachytene spermatocytes. We also detected DNMT3a2 and DNMT3b2 in round spermatids. Taken together, these data highlight the tightly regulated expression of these genes during spermatogenesis and provide evidence that DNMTs may be contributing differentially to the establishment and/or maintenance of methylation patterns in male germ cells. (c) 2006 Elsevier Inc. All rights reserved.