Taniguchi Y, Katsumata Y, Koido S, Suemizu H, Yoshimura S, Moriuchi T, Okumura K, Kagotani K, Taguchi H, Imanishi T, Gojobori T, Inoko H
Department of Molecular Life Science, Tokai University School of Medicine, Kanagawa, Japan.
Mamm Genome. 1996 Dec;7(12):906-8. doi: 10.1007/s003359900266.
We have characterized a human genomic clone carrying two pseudogenes for the proliferating cell nuclear antigen (PCNA), which were tandemly arranged on human Chromosome (Chr) 4. One is a processed pseudogene that showed a 73% nucleotide homology to the human PCNA cDNA and possessed none of the introns existing in the functional PCNA gene. This pseudogene presumably arose by reverse transcription of a PCNA mRNA followed by integration of the cDNA into the genome. The other is a 5' and 3' truncated pseudogene that showed a nucleotide homology to a 3' region of the exon 4 and to a 5' region of the exon 5 of the PCNA gene and did not have the intronic sequence between the exons 4 and 5. Both pseudogenes had the same nucleotide deletion as compared with the human functional PCNA gene. A phylogenetic analysis of PCNA gene family, including the functional PCNA gene and another PCNA pseudogene located on a different chromosome, revealed that the truncated pseudogene exhibits the closest evolutionary relationship with the processed pseudogene, suggesting that the truncated pseudogene was generated by duplication of the processed pseudogene after translocation to Chr 4. Furthermore, fluorescence in situ hybridization revealed that these pseudogenes are located on the long arm of Chr 4, 4q24.
我们鉴定了一个携带增殖细胞核抗原（PCNA）两个假基因的人类基因组克隆，这两个假基因串联排列在人类4号染色体（Chr）上。其中一个是加工假基因，与人类PCNA cDNA具有73%的核苷酸同源性，且不具备功能性PCNA基因中存在的任何内含子。这个假基因可能是由PCNA mRNA逆转录后，其cDNA整合到基因组中产生的。另一个是5'和3'端截短的假基因，与PCNA基因外显子4的3'区域和外显子5的5'区域具有核苷酸同源性，并且在第4和第5外显子之间没有内含子序列。与人类功能性PCNA基因相比，这两个假基因都有相同的核苷酸缺失。对PCNA基因家族进行系统发育分析，包括功能性PCNA基因和位于不同染色体上的另一个PCNA假基因，结果显示截短的假基因与加工假基因呈现出最密切的进化关系，这表明截短的假基因是加工假基因易位到4号染色体后通过复制产生的。此外，荧光原位杂交显示这些假基因位于4号染色体长臂4q24处。
