1. Academic Validation
  2. G364R mutation of MCM4 detected in human skin cancer cells affects DNA helicase activity of MCM4/6/7 complex

G364R mutation of MCM4 detected in human skin cancer cells affects DNA helicase activity of MCM4/6/7 complex

  • J Biochem. 2015 Jun;157(6):561-9. doi: 10.1093/jb/mvv015.
Yukio Ishimi 1 Daiki Irie 2
Affiliations

Affiliations

  • 1 College of Science, Ibaraki University, Mito, Ibaraki 351-8511, Japan ishimi@ibaraki.ac.jp.
  • 2 College of Science, Ibaraki University, Mito, Ibaraki 351-8511, Japan.
Abstract

A number of gene mutations are detected in cells derived from human Cancer tissues, but roles of these mutations in Cancer cell development are largely unknown. We examined G364R mutation of MCM4 detected in human skin Cancer cells. Formation of MCM4/6/7 complex is not affected by the mutation. Consistent with this notion, the binding to MCM6 is comparable between the mutant MCM4 and wild-type MCM4. Nuclear localization of this mutant MCM4 expressed in HeLa cells supports this conclusion. Purified MCM4/6/7 complex containing the G364R MCM4 exhibited similar levels of single-stranded DNA binding and ATPase activities to the complex containing wild-type MCM4. However, the mutant complex showed only 30-50% of DNA helicase activity of the wild-type complex. When G364R MCM4 was expressed in HeLa cells, it was fractionated into nuclease-sensitive chromatin fraction, similar to wild-type MCM4. These results suggest that this mutation does not affect assembly of MCM2-7 complex on replication origins but it interferes some step at function of MCM2-7 helicase. Thus, this mutation may contribute to Cancer cell development by disturbing DNA replication.

Keywords

DNA binding; DNA helicase; DNA replication; cancer; gene mutation.

Figures