BLM is an early responder to DNA double-strand breaks.
Bloom syndrome (BS) is an autosomal recessive disorder characterized by a marked predisposition to cancer and elevated genomic instability. The defective protein in BS, BLM, is a member of the RecQ helicase family and is believed to function in various DNA transactions, including in replication, repair, and recombination. Here, we show that both endogenous and overexpressed human BLM accumulates at sites of laser light-induced DNA double-strand breaks within 10s and colocalizes with gammaH2AX and ATM. Like its RecQ helicase family member, WRN, the defective protein in Werner syndrome, dissection of the BLM protein revealed that its HRDC domain is sufficient for its recruitment to the damaged sites. In addition, we confirmed that the C-terminal region spanning amino acids 1250-1292 within the HRDC domain is necessary for BLM recruitment. To identify additional proteins required for the recruitment of BLM, we examined the recruitment of BLM in various mutants generated from chicken DT40 cells and found that the early accumulation of BLM was not dependent on the presence of ATM, RAD17, DNA-PKcs, NBS1, XRCC3, RAD52, RAD54, or WRN. Thus, HRDC domain in DNA helicases is a common early responder to DNA double-strand breaks, enabling BLM and WRN to be involved in DNA repair.
Karmakar
Parimal
P
Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan. pkarmakar_28@yahoo.co.in
Seki
Masayuki
M
Kanamori
Makoto
M
Hashiguchi
Kazunari
K
Ohtsuki
Makoto
M
Murata
Eriko
E
Inoue
Eri
E
Tada
Shusuke
S
Lan
Li
L
Yasui
Akira
A
Enomoto
Takemi
T
D000251:Adenosine Triphosphatases / Q000235:genetics*; D020816:Amino Acid Motifs; D064007:Ataxia Telangiectasia Mutated Proteins; D001665:Binding Sites; D001816:Bloom Syndrome / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004249:DNA Damage; D004265:DNA Helicases / Q000235:genetics*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics; D049452:Green Fluorescent Proteins; D006657:Histones / Q000235:genetics; D006801:Humans; D007834:Lasers; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D025521:Tumor Suppressor Proteins / Q000235:genetics
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D025521:Tumor Suppressor Proteins; D049452:Green Fluorescent Proteins; D004247:DNA; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D000251:Adenosine Triphosphatases; C097151:Bloom syndrome protein; C506725:RECQL protein, human; D004265:DNA Helicases; D053484:RecQ Helicases