title: Purification of the human SMN-GEMIN2 complex and assessment of its stimulation of RAD51-mediated DNA recombination reactions.
abstract: A deficiency in the SMN gene product causes the motor neuron degenerative disease spinal muscular atrophy. GEMIN2 was identified as an SMN-interacting protein, and the SMN-GEMIN2 complex constitutes part of the large SMN complex, which promotes the assembly of the spliceosomal small nuclear ribonucleoprotein (snRNP). In addition to its splicing function, we previously found that GEMIN2 alone stimulates RAD51-mediated recombination in vitro, and functions in DNA double-strand-break (DSB) repair through homologous recombination in vivo. However, the function of SMN in homologous recombination has not been reported. In the present study, we successfully purified the SMN-GEMIN2 complex as a fusion protein. The SMN-GEMIN2 fusion protein complemented the growth-defective phenotype of GEMIN2-knockout cells. The purified SMN-GEMIN2 fusion protein enhanced the RAD51-mediated homologous pairing much more efficiently than GEMIN2 alone. SMN-GEMIN2 possessed DNA-binding activity, which was not observed with the GEMIN2 protein, and significantly stimulated the secondary duplex DNA capture by the RAD51-single-stranded DNA complex during homologous pairing. These results provide the first evidence that the SMN-GEMIN2 complex plays a role in homologous recombination, in addition to spliceosomal snRNP assembly.
authors: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors: Motoki
authors: M
authors: Takaku
authors: Takashi
authors: T
authors: Tsujita
authors: Naoki
authors: N
authors: Horikoshi
authors: Yoshimasa
authors: Y
authors: Takizawa
authors: Yong
authors: Y
authors: Qing
authors: Kouji
authors: K
authors: Hirota
authors: Masae
authors: M
authors: Ikura
authors: Tsuyoshi
authors: T
authors: Ikura
authors: Shunichi
authors: S
authors: Takeda
authors: Hitoshi
authors: H
authors: Kurumizaka
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens; D004247:DNA / Q000235:genetics*; D017931:DNA Primers; D004260:DNA Repair; D055786:Gene Knockout Techniques; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D016601:RNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D051135:Rad51 Recombinase / Q000302:isolation & purification* / Q000502:physiology; D011995:Recombination, Genetic / Q000502:physiology*; D055533:Survival of Motor Neuron 1 Protein / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D017931:DNA Primers; C108381:GEMIN2 protein, human; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; D055533:Survival of Motor Neuron 1 Protein; D004247:DNA; C495153:RAD51 protein, human; D051135:Rad51 Recombinase