Functional characterization of CHEK2 variants in a Saccharomyces cerevisiae system

Hum Mutat. 2019 May;40(5):631-648. doi: 10.1002/humu.23728. Epub 2019 Mar 9.

Abstract

Genetic testing for cancer predisposition leads to the identification of a number of variants with uncertain significance. To some extent, variants of BRCA1/2 have been classified, in contrast to variants of other genes. CHEK2 is a typical example, in which a large number of variants of unknown clinical significance were identified and still remained unclassified. Herein, the CHEK2 variant assessment was performed through an in vivo, yeast-based, functional assay. In total, 120 germline CHEK2 missense variants, distributed along the protein sequence, and two large in-frame deletions were tested, originating from genetic test results in breast cancer families, or selected from the ClinVar database. Of these, 32 missense and two in-frame deletions behaved as non-functional, 73 as functional, and 15 as semi-functional, after comparing growth rates of each strain with positive and negative controls. The majority of non-functional variants were localized in the CHK2 kinase and forkhead-associated domains. In vivo results from the non-functional variants were in agreement with in silico predictions, and, where available, with strong breast cancer family history, to a great extent. The results of the largest, to date, yeast-based assay, evaluating CHEK2 variants, can complement and assist in the classification of rare CHEK2 variants with unclear clinical significance.

Keywords: CHEK2 variants; breast cancer; functional assay; yeast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Substitution
  • Checkpoint Kinase 2 / genetics*
  • Checkpoint Kinase 2 / metabolism
  • Computational Biology / methods
  • Gene Frequency
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Humans
  • Models, Molecular
  • Mutation*
  • Pedigree
  • Protein Conformation
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism

Substances

  • Checkpoint Kinase 2
  • CHEK2 protein, human