Open AccessHuman CDC45 protein binds to minichromosome maintenance 7 protein and the p70 subunit of DNA polymerase α
Author(s) -
Kukimoto Iwao,
Igaki Hiroshi,
Kanda Tadahito
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00791.x
Subject(s) - biology , microbiology and biotechnology , minichromosome maintenance , eukaryotic dna replication , origin recognition complex , dna polymerase , dna replication , dna polymerase delta , dna polymerase ii , replication factor c , control of chromosome duplication , genetics , gene , reverse transcriptase , polymerase chain reaction
Budding yeast CDC45 encodes Cdc45p, an essential protein required to trigger initiation of DNA replication in late G1 phase. We cloned four and one species of the human Cdc45p homolog cDNA, resulting from different splicing patterns, from HeLa cell and human placenta cDNA libraries, respectively. A comparison of the cDNAs and the genomic sequence showed that the longest encoding a 610‐amino acid protein was comprised of 20 exons. One species, which lacks exon 7 and contains the shorter of two exons 18, was identical with the previously reported CDC45L cDNA and constituted 24 out of 28 clones from HeLa cells. Splicing was different in HeLa cells and TIG‐1 cells, a human diploid cell line. Human CDC45 protein was found to bind directly in vitro to human minichromosome maintenance 7 protein (hMCM7) and to the p70 subunit of DNA polymerase α. The data support a thesis that human CDC45 acts as a molecular tether to mediate loading of the DNA polymerase α on to the DNA replication complex through binding to hMCM7.