McBride O W, Pirtle I L, Pirtle R M
Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892.
Genomics. 1989 Oct;5(3):561-73. doi: 10.1016/0888-7543(89)90024-4.
The chromosomal locations of three cloned human DNA fragments encompassing tRNA genes have been determined by Southern analysis of human-rodent somatic cell hybrid DNAs with subfragments from these cloned genes and flanking sequences used as hybridization probes. These three DNA segments have been assigned to human chromosomes 1, 5, and 16, and homologous sequences are probably located on chromosome 14 and a separate locus on chromosome 1. These studies, combined with previous results, indicate that tRNA genes and pseudogenes are dispersed on at least seven different human chromosomes and suggest that these sequences will probably be found on most, if not all, human chromosomes. Short (8-12 nucleotide) direct terminal repeats flank many of the dispersed tRNA genes. The presence of these flanking repeats, combined with the dispersion of tRNA genes throughout the human genome, suggests that many of these genes may have arisen by an RNA-mediated retroposition mechanism. The possible functional significance of this gene dispersion is considered.
通过用这些克隆基因的亚片段和侧翼序列作为杂交探针，对人-啮齿动物体细胞杂种DNA进行Southern分析，已确定了包含tRNA基因的三个克隆人DNA片段的染色体定位。这三个DNA区段已被定位到人类染色体1、5和16上，并且同源序列可能位于染色体14和染色体1上的一个单独位点。这些研究与先前的结果相结合，表明tRNA基因和假基因分散在至少七条不同的人类染色体上，并表明这些序列很可能会在大多数（如果不是全部）人类染色体上被发现。许多分散的tRNA基因两侧有短（8 - 12个核苷酸）的直接末端重复序列。这些侧翼重复序列的存在，加上tRNA基因在整个人类基因组中的分散，表明这些基因中的许多可能是通过RNA介导的逆转座机制产生的。本文考虑了这种基因分散可能具有的功能意义。
