Analysis of a FANCE Splice Isoform in Regard to DNA Repair.
The FANC-BRCA DNA repair pathway is activated in response to interstrand crosslinks formed in DNA. A homozygous mutation in 1 of the 17 Fanconi anemia (FA) genes results in malfunctions of this pathway and development of FA syndrome. The integrity of this protein network is essential for good maintenance of DNA repair process and genome stability. Following the identification of an alternatively splice isoform of FANCE (Fanconi anemia complementation group E) significantly expressed in breast cancer individuals from high-risk non-BRCA1/2 families, we studied the impact of this FANCE splice isoform (FANCEΔ4) on DNA repair processes. We have demonstrated that FANCEΔ4 mRNA was efficiently translated into a functional protein and expressed in normal and breast cancer cell lines. Following treatment with the crosslinking agent mitomycin C, EUFA130 (FANCE-deficient) cells infected with FANCEΔ4 were blocked into G2/M phase, while cell survival was significantly reduced compared with FANCE-infected EUFA130 cells. In addition, FANCEΔ4 did not allow FANCD2 and FANCI monoubiquitination, which represents a crucial step of the FANC-BRCA functional pathway. As observed for FANCE wild-type protein, localization of FANCEΔ4 protein was confined to the nucleus following mitomycin C treatment. Although FANCEΔ4 protein showed interaction with FANCE, FANCEΔ4 did not support normal function of FANCE protein in this pathway and could have deleterious effects on FANCE protein activity. We have demonstrated that FANCEΔ4 seems to act as a regulator of FANCD2 protein expression level by promoting its degradation. This study highlights the importance of an efficient regulation of alternative splicing expression of FA genes for proper DNA repair.
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2.
Frédérick
F
Bouffard
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2.
Karine
K
Plourde
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2.
Simon
S
Bélanger
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2.
Geneviève
G
Ouellette
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2.
Yvan
Y
Labrie
CHU de Québec Research Centre and Laval University, Québec City, QC, Canada G1V 4G2. Electronic address: francine.durocher@crchudequebec.ulaval.ca.
Francine
F
Durocher
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D019313:BRCA1 Protein / Q000378:metabolism; D024682:BRCA2 Protein / Q000378:metabolism; D002470:Cell Survival; D004260:DNA Repair; D005199:Fanconi Anemia / Q000235:genetics* / Q000378:metabolism; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics; D052239:Fanconi Anemia Complementation Group E Protein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D019313:BRCA1 Protein; D024682:BRCA2 Protein; D052236:Fanconi Anemia Complementation Group D2 Protein; D052239:Fanconi Anemia Complementation Group E Protein; D051856:Fanconi Anemia Complementation Group Proteins; D020033:Protein Isoforms
DNA repair; FANCE; Fanconi anemia; alternative splicing