NUCKS1 is a novel RAD51AP1 paralog important for homologous recombination and genome stability.
NUCKS1 (nuclear casein kinase and cyclin-dependent kinase substrate 1) is a 27 kD chromosomal, vertebrate-specific protein, for which limited functional data exist. Here, we demonstrate that NUCKS1 shares extensive sequence homology with RAD51AP1 (RAD51 associated protein 1), suggesting that these two proteins are paralogs. Similar to the phenotypic effects of RAD51AP1 knockdown, we find that depletion of NUCKS1 in human cells impairs DNA repair by homologous recombination (HR) and chromosome stability. Depletion of NUCKS1 also results in greatly increased cellular sensitivity to mitomycin C (MMC), and in increased levels of spontaneous and MMC-induced chromatid breaks. NUCKS1 is critical to maintaining wild type HR capacity, and, as observed for a number of proteins involved in the HR pathway, functional loss of NUCKS1 leads to a slow down in DNA replication fork progression with a concomitant increase in the utilization of new replication origins. Interestingly, recombinant NUCKS1 shares the same DNA binding preference as RAD51AP1, but binds to DNA with reduced affinity when compared to RAD51AP1. Our results show that NUCKS1 is a chromatin-associated protein with a role in the DNA damage response and in HR, a DNA repair pathway critical for tumor suppression.
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Ann C
AC
Parplys
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
Weixing
W
Zhao
Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Neelam
N
Sharma
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Torsten
T
Groesser
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
Fengshan
F
Liang
Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
David G
DG
Maranon
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Stanley G
SG
Leung
Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, 0317 Oslo, Norway.
Kirsten
K
Grundt
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
Eloïse
E
Dray
Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Rupa
R
Idate
Department of Molecular Medicine, Institute of Basic Medical Science, University of Oslo, 0317 Oslo, Norway.
Anne Carine
AC
Østvold
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
David
D
Schild
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
Patrick
P
Sung
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA Claudia.Wiese@colostate.edu.
Claudia
C
Wiese
D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D002869:Chromosome Aberrations; D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology; D042822:Genomic Instability; D006367:HeLa Cells / Q000502:physiology; D006801:Humans; D016685:Mitomycin / Q000494:pharmacology; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation / Q000528:radiation effects; D016601:RNA-Binding Proteins; D051135:Rad51 Recombinase / Q000378:metabolism; D059767:Recombinational DNA Repair; D016196:S Phase / Q000528:radiation effects; D017386:Sequence Homology, Amino Acid; D014965:X-Rays
D002843:Chromatin; D004268:DNA-Binding Proteins; C426654:NUCKS1 protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; C110410:RAD51AP1 protein, human; D016601:RNA-Binding Proteins; D016685:Mitomycin; D004247:DNA; D051135:Rad51 Recombinase