Cleavage of rRNA ensures translational cessation in sperm at fertilization
Cleavage of rRNA ensures translational cessation in sperm at fertilization
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DOI：
10.1093/molehr/gar054
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发表时间：
2011-12-01
影响因子：
4
通讯作者：
Krawetz, S. A.
中科院分区：
文献类型：
--
作者：
Johnson, G. D.;Sendler, E.;Krawetz, S. A.
完整的核糖体RNAs(RRNAs)构成了大多数体细胞转录本，但在精子中明显缺失，这可能反映了精子发生过程中细胞质的排出。为了弄清它们的命运，对三个有生育能力的捐赠者的成熟精子中保留的总RNA进行了下一代测序。在所有样本中，75%的总序列读数与rRNA比对。沿着这些成绩单长度的读数分布显示出高度不一致，这在捐赠者之间反复出现。测序读数的覆盖率与鸟嘌呤胞嘧啶(GC)的丰度呈负相关，以至于在所有精子RNA样本中，几乎没有大于70%GC的序列。为了证实序列的缺失，用7-脱氧-2‘-脱氧鸟苷-5’-三磷酸RT-PCR方法建立了精子中28S转录本特定区域的相对丰度。尽管28S转录本在测序文库中有丰富的表达，但无法从精子中扩增出28S序列的特定区域，这表明成熟雄配子中约四分之三的RNA是rRNA片断的产物。因此，切割(而不是翻译机制的RNA成分的排出)负责防止精子发生后的虚假翻译。这些结果突显了这些转录本的潜在重要性，包括许多mRNAs，当精子在受精时传递时，这些转录物可以避免碎片并保持完整。测序数据存放在GEO中，编号为：GSE29160。
Intact ribosomal RNAs (rRNAs) comprise the majority of somatic transcripts, yet appear conspicuously absent in spermatozoa, perhaps reflecting cytoplasmic expulsion during spermatogenesis. To discern their fate, total RNA retained in mature spermatozoa from three fertile donors was characterized by Next Generation Sequencing. In all samples, >75% of total sequence reads aligned to rRNAs. The distribution of reads along the length of these transcripts exhibited a high degree of non-uniformity that was reiterated between donors. The coverage of sequencing reads was inversely correlated with guanine-cytosine (GC)-richness such that sequences greater than similar to 70% GC were virtually absent in all sperm RNA samples. To confirm the loss of sequence, the relative abundance of specific regions of the 28S transcripts in sperm was established by 7-Deaza-2'-deoxy-guanosine-5'-triphosphate RT-PCR. The inability to amplify specific regions of the 28S sequence from sperm despite the abundant representation of this transcript in the sequencing libraries demonstrates that approximately three-quarters of RNA retained in the mature male gamete are products of rRNA fragmentation. Hence, cleavage (not expulsion of the RNA component of the translational machinery) is responsible for preventing spurious translation following spermiogenesis. These results highlight the potential importance of those transcripts, including many mRNAs, which evade fragmentation and remain intact when sperm are delivered at fertilization. Sequencing data are deposited in GEO as: GSE29160.