Human testis expresses a specific poly(A)-binding protein
Human testis expresses a specific poly(A)-binding protein
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DOI：
10.1093/nar/29.9.1872
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发表时间：
2001-05-01
影响因子：
14.9
通讯作者：
Pawlak, A
中科院分区：
文献类型：
--
作者：
Féral, C;Guellaën, G;Pawlak, A
在睾丸中，mRNA 的稳定性和翻译起始很大程度上受到多聚腺苷酸结合蛋白 (PABP) 的控制。在这里，我们克隆了一种新的人类睾丸特异性 PABP (PABP3)，由 631 个氨基酸 (70.1 kDa) 组成，与普遍存在的 PABP1 具有 92.5% 的残基相同性。与 PABP3 和 PABP1 特异性寡核苷酸探针杂交的多个人体组织的 Northern 印迹显示，仅在睾丸中检测到两种 PABP3 mRNA（2.1 和 2.5 kb），而 PABP1 mRNA（3.2 kb）存在于所有测试组织中。在成人睾丸中，PABP3 mRNA 表达仅限于圆形精子细胞，而 PABP1 在这些细胞以及粗线期精母细胞中表达，PABP3 特异性抗体在人睾丸提取物中鉴定出 70 kDa 的蛋白质。与 PABP1 相比，该蛋白与 Poly(A) 的结合亲和力略低。人 PABP3 基因无内含子，转录起始位点位于起始密码子上游 61 nt 处。转录起始位点上游 256 bp 的序列驱动 PABP3 的启动子活性及其组织特异性表达。 PABP3 的表达可能是绕过 PABP1 翻译抑制并在精子细胞中产生活性 mRNA 翻译所需的 PABP 量的一种方式。
In testis mRNA stability and translation initiation are extensively under the control of poly(A)-binding proteins (PABP). Here we have cloned a new human testis-specific PABP (PABP3) of 631 amino acids (70.1 kDa) with 92.5% identical residues to the ubiquitous PABP1. A northern blot of multiple human tissues hybridised with PABP3- and PABP1-specific oligonucleotide probes revealed two PABP3 mRNAs (2.1 and 2.5 kb) detected only in testis, whereas PABP1 mRNA (3.2 kb) was present in all tested tissues. In human adult testis, PABP3 mRNA expression was restricted to round spermatids, whereas PABP1 was expressed in these cells as well as in pachytene spermatocytes, PABP3-specific antibodies identified a protein of 70 kDa in human testis extracts. This protein binds poly(A) with a slightly lower affinity as compared to PABP1. The human PABP3 gene is intronless with a transcription start site 61 nt upstream from the initiation codon. A sequence of 256 bp upstream from the transcription start site drives the promoter activity of PABP3 and its tissue-specific expression. The expression of PABP3 might be a way to bypass PABP1 translational repression and to produce the amount of PABP needed for active mRNA translation in spermatids.