Tsunekawa N, Matsumoto M, Tone S, Nishida T, Fujimoto H
Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo, Japan.
Mol Reprod Dev. 1999 Apr;52(4):383-91. doi: 10.1002/(SICI)1098-2795(199904)52:4<383::AID-MRD7>3.0.CO;2-Z.
Hsc70t is a member of the Hsp70 family of genes and is constitutively expressed after meiosis in mouse spermatogenesis. Immunohistochemistry and in situ hybridization techniques were used to examine the precise localization of the Hsc70t product during the various stages of spermatogenesis. A rabbit antiserum raised againstthe mouse Hsc70t-lacZ fusion protein detected the Hsc70t protein in the late spermatid-enriched fraction after two-dimensional Western blot analyses. On histological sections, the protein appears in the cytoplasm of spermatids as they progress from step 9 to the final step of spermatogenesis. An antisense RNA probe generated from the 3' untranslated region of Hsc70t cDNA detected Hsc70t mRNA in late round spermatids from step 7 onward with the signal disappearing in spermatids at step 15. Thus, Hsc70t mRNA first appears after meiosis in haploid cells but is not translated effectively until these cells progress to the transcriptionally inactive stage which coincides with chromatin condensation. These results establish that the synthesis of Hsc70t protein is under strict translational control.
Hsc70t是热休克蛋白70（Hsp70）基因家族的成员，在小鼠精子发生减数分裂后持续表达。采用免疫组织化学和原位杂交技术检测Hsc70t产物在精子发生各个阶段的精确定位。经二维蛋白质印迹分析，用针对小鼠Hsc70t - lacZ融合蛋白制备的兔抗血清在富含晚期精子细胞的组分中检测到了Hsc70t蛋白。在组织学切片上，随着精子细胞从第9阶段发育到精子发生的最后阶段，该蛋白出现在精子细胞的细胞质中。从Hsc70t cDNA的3'非翻译区产生的反义RNA探针在第7阶段以后的晚期圆形精子细胞中检测到Hsc70t mRNA，信号在第15阶段的精子细胞中消失。因此，Hsc70t mRNA在减数分裂后首次出现在单倍体细胞中，但直到这些细胞进入与染色质浓缩同时发生的转录非活跃阶段才有效翻译。这些结果表明，Hsc70t蛋白的合成受到严格的翻译控制。
