Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
FEBS Lett. 2010 Aug 20;584(16):3509-12. doi: 10.1016/j.febslet.2010.07.046. Epub 2010 Aug 3.
In non-mammalian eukaryotes, an abnormally long 3' untranslated region (UTR) is generally thought to be the definitive signal in the recognition of a premature termination codon (PTC) in nonsense-mediated mRNA decay (NMD). However, because the lengths of 3' UTRs in normal mRNAs are widely distributed, "abnormally long" is hard to define. Distinct peaks of nucleosome deposition and DNA methylation have recently been found at coding region boundaries. We propose that nucleosomes and DNA methylation just upstream of a normal stop codon are ideal indicators for the position of a normal stop codon and may thus serve as signals in PTC recognition.
在非哺乳动物真核生物中，通常认为异常长的 3' 非翻译区 (UTR) 是在无义介导的 mRNA 降解 (NMD) 中识别终止密码子 (PTC) 的明确信号。然而，由于正常 mRNA 的 3'UTR 长度分布广泛，“异常长”很难定义。最近在编码区边界处发现了核小体沉积和 DNA 甲基化的明显峰。我们提出，正常终止密码子上游的核小体和 DNA 甲基化是正常终止密码子位置的理想指标，因此可以作为 PTC 识别的信号。
