Prevalence and functional analysis of sequence variants in the ATR checkpoint mediator Claspin.
Mutational inactivation of genes controlling the DNA-damage response contributes to cancer susceptibility within families and within the general population as well as to sporadic tumorigenesis. Claspin (CLSPN) encodes a recently recognized mediator protein essential for the ATR and CHK1-dependent checkpoint elicited by replicative stress or the presence of ssDNA. Here, we describe a study to determine whether mutational disruption of CLSPN contributes to cancer susceptibility and sporadic tumorigenesis. We resequenced CLSPN from the germline of selected cancer families with a history of breast cancer (n = 25) or a multicancer phenotype (n = 46) as well as from a panel of sporadic cancer cell lines (n = 52) derived from a variety of tumor types. Eight nonsynonymous variants, including a recurrent mutation, were identified from the germline of two cancer-prone individuals and five cancer cell lines of breast, ovarian, and hematopoietic origin. None of the variants was present within population controls. In contrast, mutations were rare within genes encoding the CLSPN-interacting protein ATR and its binding partner ATRIP. One variant of CLSPN, encoding the I783S missense mutation, was defective in its ability to mediate CHK1 phosphorylation following DNA damage and was unable to rescue sensitivity to replicative stress in CLSPN-depleted cells. Taken together, these observations raise the possibility that CLSPN may encode a component of the DNA-damage response pathway that is targeted by mutations in human cancers, suggesting the need for larger population-based studies to investigate whether CLSPN variants contribute to cancer susceptibility.
Zhang
Jianmin
J
Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
Song
Young-Han
YH
Brannigan
Brian W
BW
Wahrer
Doke C R
DC
Schiripo
Taryn A
TA
Harris
Patricia L
PL
Haserlat
Sara M
SM
Ulkus
Lindsey E
LE
Shannon
Kristen M
KM
Garber
Judy E
JE
Freedman
Matthew L
ML
Henderson
Brian E
BE
Zou
Lee
L
Sgroi
Dennis C
DC
Haber
Daniel A
DA
Bell
Daphne W
DW
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D004252:DNA Mutational Analysis / Q000379:methods; D004268:DNA-Binding Proteins / Q000235:genetics*; D005190:Family; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D015151:Immunoblotting; D020125:Mutation, Missense; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D015995:Prevalence; D011494:Protein Kinases / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D014407:Tumor Cells, Cultured
C521194:ATRIP protein, human; D048868:Adaptor Proteins, Signal Transducing; C488158:CLSPN protein, human; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1