The silencing of pseudogenes
The silencing of pseudogenes
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DOI：
10.1093/molbev/msi209
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发表时间：
2005-11-01
影响因子：
10.7
通讯作者：
Pushker, R
中科院分区：
文献类型：
--
作者：
Mira, A;Pushker, R
假基因是一些细菌基因组中积累的非功能性DNA序列，特别是那些经历生态位变化、宿主特化或弱选择强度的细菌。它们可能会持续很长时间的进化，这就提出了一个问题：基因组是如何阻止这些退化或被破坏的基因的表达的，而这些基因可能会产生功能失调的蛋白质。我们研究了Shine-Dalgarno序列的核糖体结合强度和细菌中假基因中sigma（70）启动子区域的患病率。据报道，假基因的RNA聚合酶结合位点和核糖体结合区被高度降解，这表明在无功能的开放阅读框中转录和翻译受到损害。这将减少对错误蛋白质的代谢投资，因为尽管假基因可以持续很长一段时间，但它们将被有效地沉默。目前尚不清楚调控区域的突变积累是中性的还是通过选择加速的。
Pseudogenes are nonfunctional DNA sequences that can accumulate in the genomes of some bacterial species, especially those undergoing processes like niche change, host specialization, or weak selection strength. They may last for long evolutionary periods, opening the question of how the genome prevents expression of these degenerated or disrupted genes that would presumably give rise to malfunctioning proteins. We have investigated ribosomal binding strength at Shine-Dalgarno sequences and the prevalence of sigma(70) promoter regions in pseudogenes across bacteria. It is reported that the RNA polymerase-binding sites and more strongly the ribosome-binding regions of pseudogenes are highly degraded, suggesting that transcription and translation are impaired in nonfunctional open reading frames. This would reduce the metabolic investment on faulty proteins because although pseudogenes can persist for long time periods, they would be effectively silenced. It is unclear whether mutation accumulation on regulatory regions is neutral or whether it is accelerated by selection.