Transgenic expression of testis-specific poly(A) polymerase TPAP in wild-type and TPAP-deficient mice
Transgenic expression of testis-specific poly(A) polymerase TPAP in wild-type and TPAP-deficient mice
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DOI：
10.1262/jrd.50.207
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发表时间：
2004-04-01
影响因子：
1.8
通讯作者：
Baba, T
中科院分区：
文献类型：
--
作者：
Zhuang, TG;Kashiwabara, S;Baba, T
我们之前已经确定了睾丸特异性聚(a)聚合酶TPAP (PAPbeta)，参与圆形精子细胞质中特定mrna的聚(a)尾部延伸。有针对性地破坏小鼠TPAP基因，由于生殖细胞形态发生所需的单倍体特异性基因的表达减少，导致精子发生受阻。为了进一步阐明TPAP在精子发生中的作用，我们在野生型和TPAP缺乏的背景下产生并鉴定了表达外源TPAP转基因小鼠。过表达TPAP的转基因小鼠表现出正常的精子发生和生育能力。作为TPAP底物的一些转录因子mrna的大小也不受影响。TPAP基因的转基因表达在TPAP缺陷小鼠中补充了特异性转录因子mrna多(A)尾的不完全伸长，以及单倍体特异性基因的表达减少，从而恢复正常的精子发生。这些数据确凿地表明，精子发生需要TPAP催化的细胞质mRNA多聚(A)尾部的伸长，并暗示存在一种确定细胞质mRNA多聚腺苷化程度的调节机制。
We have previously identified a testis-specific poly(A) polymerase, TPAP (PAPbeta), involved in poly(A) tail extension of specific mRNAs in the cytoplasm of round spermatids. Targeted disruption of the mouse TPAP gene resulted in the arrest of spermiogenesis due to reduced expression of haploid-specific genes required for morphogenesis of germ cells. To further elucidate the role(s) of TPAP in spermatogenesis, transgenic mice expressing an exogenous TPAP transgene on wild-type and TPAP-deficient backgrounds were generated and characterized. The transgenic mice overexpressing TPAP exhibited normal spermatogenesis and fertility. The sizes of some transcription factor mRNAs as the substrates of TPAP were also unaffected. Transgenic expression of the TPAP gene in the TPAP-deficient mice complemented both the incomplete elongation of the poly(A) tails of specific transcription factor mRNAs, and reduced expression of haploid-specific genes, resulting in the resumption of normal spermiogenesis. These data conclusively show that spermatogenesis requires the cytoplasmic elongation of the mRNA poly(A) tails catalyzed by TPAP, and imply the presence of a regulatory mechanism(s) defining the extent of the cytoplasmic mRNA polyadenylation.