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首页> 外文期刊>Molecular and Cellular Biology >Developmentally Regulated Telomerase Activity Is Correlated with Chromosomal Healing during Chromatin Diminution inAscaris suum
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Developmentally Regulated Telomerase Activity Is Correlated with Chromosomal Healing during Chromatin Diminution inAscaris suum

机译：A虫染色质减少过程中发育调控的端粒酶活性与染色体修复相关。

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Telomerase is the ribonucleoprotein complex responsible for the maintenance of the physical ends, or telomeres, of most eukaryotic chromosomes. In this study, telomerase activity has been identified in cell extracts from the nematode Ascaris suum. This parasitic nematode is particularly suited as a model system for the study of telomerase, because it shows the phenomenon of chromatin diminution, consisting of developmentally programmed chromosomal breakage, DNA elimination, and new telomere formation. In vitro, the A. suum telomerase is capable of efficiently recognizing and elongating nontelomeric primers with nematode-specific telomere repeats by using limited homology at the 3′ end of the DNA to anneal with the putative telomerase RNA template. The activity of this enzyme is developmentally regulated, and it correlates temporally with the phenomenon of chromatin diminution. It is up-regulated during the first two rounds of embryonic cell divisions, to reach a peak in 4-cell-stage embryos, when three presomatic blastomeres prepare for chromatin diminution. The activity remains high until the beginning of gastrulation, when the last of the presomatic cells undergoes chromatin diminution, and then constantly decreases during further development. In summary, our data strongly argue for a role of this enzyme in chromosome healing during the process of chromatin diminution.
机译：端粒酶是核糖核蛋白复合物，负责维持大多数真核染色体的物理末端或端粒。在这项研究中，已从线虫 Ascaris suum 的细胞提取物中鉴定出端粒酶活性。这种寄生线虫特别适合用作端粒酶研究的模型系统，因为它显示出染色质减少的现象，包括发育中的程序性染色体断裂，DNA消除和新的端粒形成。在体外， A。 suum 端粒酶能够通过在DNA的3'端使用有限的同源性与假定的端粒酶RNA模板进行退火，从而有效地识别和延长具有线虫特异性端粒重复序列的非端粒引物。该酶的活性受发育调节，并且在时间上与染色质减少现象相关。在前两个回合的胚胎细胞分裂过程中，当三个早体型卵裂球准备减少染色质时，它会在4细胞阶段的胚胎中达到峰值。该活性一直保持高水平，直到开始胃化之前，当最后的前体细胞经历染色质减薄，然后在进一步发育过程中不断降低。总而言之，我们的数据强烈证明了该酶在染色质减少过程中在染色体修复中的作用。

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