López I, Khan S, Vázquez J, Hussey P J
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F.
Biochim Biophys Acta. 1997 Jul 17;1353(1):1-6. doi: 10.1016/s0167-4781(97)00072-9.
PCNA is an auxilliary protein for DNA polymerase delta whose function is to increase both polymerase activity and processivity. We have previously reported the isolation of a maize cDNA clone encoding a homologue of PCNA. Here we report the identification of a second maize PCNA cDNA clone. The nucleic acid sequence of both clones is almost identical in the coding sequences, showing 94% identity, but differs by approximately 40% in the 5' and 3' non-translated regions. Maize genomic Southern blots probed with the complete cDNAs and gene-specific probes revealed that maize contains two PCNA genes. Northern blots of RNA extracted from different plant tissues show that both genes are equally expressed in proliferating tissues.
增殖细胞核抗原（PCNA）是DNA聚合酶δ的一种辅助蛋白，其功能是提高聚合酶活性和持续合成能力。我们之前报道过分离出一个编码PCNA同源物的玉米cDNA克隆。在此我们报告鉴定出第二个玉米PCNA cDNA克隆。两个克隆的核酸序列在编码序列上几乎相同，同一性为94%，但在5'和3'非翻译区相差约40%。用完整cDNA和基因特异性探针探测的玉米基因组Southern杂交结果显示，玉米含有两个PCNA基因。从不同植物组织提取的RNA的Northern杂交结果表明，这两个基因在增殖组织中表达水平相当。
