Recruitment and retention dynamics of RECQL5 at DNA double strand break sites.
RECQL5 is one of the five human RecQ helicases, involved in the maintenance of genomic integrity. While much insight has been gained into the function of the Werner (WRN) and Bloom syndrome proteins (BLM), little is known about RECQL5. We have analyzed the recruitment and retention dynamics of RECQL5 at laser-induced DNA double strand breaks (DSBs) relative to other human RecQ helicases. RECQL5-depleted cells accumulate persistent 53BP1 foci followed by γ-irradiation, indicating a potential role of RECQL5 in the processing of DSBs. Real time imaging of live cells using confocal laser microscopy shows that RECQL5 is recruited early to laser-induced DSBs and remains for a shorter duration than BLM and WRN, but persist longer than RECQL4. These studies illustrate the differential involvement of RecQ helicases in the DSB repair process. Mapping of domains within RECQL5 that are necessary for recruitment to DSBs revealed that both the helicase and KIX domains are required for DNA damage recognition and stable association of RECQL5 to the DSB sites. Previous studies have shown that MRE11 is essential for the recruitment of RECQL5 to the DSB sites. Here we show that the recruitment of RECQL5 does not depend on the exonuclease activity of MRE11 or on active transcription by RNA polymerase II, one of the prominent interacting partners of RECQL5. Also, the recruitment of RECQL5 to laser-induced damage sites is independent of the presence of other DNA damage signaling and repair proteins BLM, WRN and ATM.
Laboratory of Molecular Gerontology, National Institute on Aging, NIH, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA.
Venkateswarlu
V
Popuri
Mahesh
M
Ramamoorthy
Takashi
T
Tadokoro
Dharmendra Kumar
DK
Singh
Parimal
P
Karmakar
Deborah L
DL
Croteau
Vilhelm A
VA
Bohr
D002460:Cell Line; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D005090:Exodeoxyribonucleases / Q000378:metabolism; D005720:Gamma Rays / Q000009:adverse effects; D020868:Gene Silencing; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007700:Kinetics; D007834:Lasers / Q000009:adverse effects; D000076228:MRE11 Homologue Protein; D054730:Protein Interaction Domains and Motifs / Q000502:physiology; D012319:RNA Polymerase II / Q000378:metabolism; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism*; D000071857:Tumor Suppressor p53-Binding Protein 1; D000071657:Werner Syndrome Helicase
D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C121766:MRE11 protein, human; C506732:RECQL5 protein, human; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D012319:RNA Polymerase II; D005090:Exodeoxyribonucleases; D000076228:MRE11 Homologue Protein; C097151:Bloom syndrome protein; C506731:RECQL4 protein, human; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase