Zhang Zhonghua, Xue Qingzhong
James D. Watson Institute of Genome Science, Zhejiang University, Hangzhou 310008, China.
Biosystems. 2005 Dec;82(3):248-56. doi: 10.1016/j.biosystems.2005.08.002. Epub 2005 Oct 13.
Tri-nucleotide repeats (TNRs) are extremely abundant in rice genome, of which CCG/CGG repeats have an advantage over other repeats, with approximate half of all the TNRs in the genome. Our results show that rice genome has relatively abundant TNRs with high GC content, and containing only purines or pyrimidines under the same GC content. The AAT/ATT repeats that occur predominantly in intergenic and intronic regions have a considerably higher average length than that of other repeats. The highest frequency of TNRs occurs in 5'-UTR regions, followed by in coding and 5'-flanking regions. Purines-rich TNRs prefer to the coding regions, but pyrimidines-rich TNRs exhibit a stronger bias to upstream regions, suggesting that they might be considered as the regulatory elements in gene expression. As if TNRs located predominantly near the start of coding regions do not significantly influence on the protein function.
三核苷酸重复序列（TNRs）在水稻基因组中极为丰富，其中CCG/CGG重复序列相对于其他重复序列具有优势，约占基因组中所有TNRs的一半。我们的研究结果表明，水稻基因组具有相对丰富的、GC含量高的TNRs，并且在相同GC含量下仅包含嘌呤或嘧啶。主要出现在基因间区和内含子区域的AAT/ATT重复序列的平均长度比其他重复序列长得多。TNRs出现频率最高的区域是5'-UTR区，其次是编码区和5'-侧翼区。富含嘌呤的TNRs倾向于编码区，但富含嘧啶的TNRs对上游区域表现出更强的偏好，这表明它们可能被视为基因表达中的调控元件。似乎主要位于编码区起始附近的TNRs对蛋白质功能没有显著影响。
