The N-terminal internal region of BLM is required for the formation of dots/rod-like structures which are associated with SUMO-1.
Bloom Syndrome (BS) is a human autosomal genetic disorder characterized by a predisposition to a variety of malignant tumors. The gene responsible for BS encodes a protein (BLM) consisting of 1417 amino acids with a nuclear localization signal in the C-terminal region, which is a member of the RecQ helicase family. We previously showed, using a yeast two-hybrid system, that BLM interacted with Ubc9, which is the conjugating enzyme of SUMO-1 (small ubiquitin-related modifier-1). In the present study, we exogenously expressed a green fluorescent protein-tagged Bloom syndrome protein, GFP-BLM, in human 293EBNA cells and found that it formed dots/rod-like structures associated with SUMO-1 in the nucleus. Deletion experiments indicated that the region from amino acids 238 to 586 of BLM is required for the formation of dots/rod-like structures associated with SUMO-1, and the DNA helicase domain, but not the helicase activity itself, slightly affected the formation and/or stability of these structures. Expression of a GFP-BLM which contained the 238-586 region, but lacked the C-terminal nuclear localization signal, resulted in localization to the cytoplasm without the formation of dots/rod-like structures and association with SUMO-1, indicating that these events occur only in the nucleus.
Suzuki
H
H
Molecular Cell Biology Laboratory, Tohoku University, Sendai, Miyagi, 980-8578, Japan.
Seki
M
M
Kobayashi
T
T
Kawabe Yi
Kaneko
H
H
Kondo
N
N
Harata
M
M
Mizuno
S
S
Masuko
T
T
Enomoto
T
T
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry / Q000648:ultrastructure; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D025842:SUMO-1 Protein; D014162:Transfection; D014452:Ubiquitins / Q000032:analysis*
D008164:Luminescent Proteins; D025842:SUMO-1 Protein; D014452:Ubiquitins; D049452:Green Fluorescent Proteins; D000251:Adenosine Triphosphatases; C097151:Bloom syndrome protein; D004265:DNA Helicases; D053484:RecQ Helicases