Chromatin remodeling factor encoded by ini1 induces G1 arrest and apoptosis in ini1-deficient cells.
Ini1/hsnf5 gene encodes INI1 protein, a chromatin remodeling factor associated with the SWI/SNF complex. In yeast, this complex modifies chromatin condensation to coactivate various transcriptional factors. However, in human, little is known about the SWI/SNF complex and INI1. To elucidate cellular functions of ini1, we constructed a recombinant adenovirus (AdexHA-INI1) capable of overexpressing INI1 in ini1-deficient cells. AdexHA-INI1 produced intranuclear INI1 in three ini1-deficient cell lines, changed their morphology, and decreased the proportion of viable cells. Flow cytometry and a BrdU incorporation assay showed that after the infection, growth of these cells was partially arrested at G1. In two of the three ini1-deficient cell lines, apoptosis was found to occur after the infection, as detected by the presence of cleaved poly (ADP-ribose) polymerase. To determine functional domains of INI1, we constructed plasmids expressing INI1 and its deletion mutants, which were used for a colony formation assay. Repeats 1 and 2 of INI1 were found to be required to suppress the growth of the three ini1-deficient cell lines. The results support the hypothesis that ini1 is a tumor suppressor gene and suggest a novel link between human SWI/SNF chromatin remodeling complex and apoptosis.
Ae
Keisuke
K
Division of Molecular Genetics, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan.
Kobayashi
Noriko
N
Sakuma
Ryuta
R
Ogata
Toshihiko
T
Kuroda
Hiroshi
H
Kawaguchi
Noriyoshi
N
Shinomiya
Kenichi
K
Kitamura
Yoshihiro
Y
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D002648:Child; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone; D003114:Colony-Forming Units Assay; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins; D005434:Flow Cytometry; D016193:G1 Phase / Q000235:genetics / Q000502:physiology*; D016147:Genes, Tumor Suppressor; D005822:Genetic Vectors / Q000235:genetics; D006367:HeLa Cells / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D010957:Plasmids / Q000235:genetics; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000502:physiology; D018335:Rhabdoid Tumor / Q000473:pathology; D012208:Rhabdomyosarcoma / Q000473:pathology; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000502:physiology; D000071796:SMARCB1 Protein; D017384:Sequence Deletion; D014157:Transcription Factors / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000648:ultrastructure
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D017412:Ribonucleoprotein, U1 Small Nuclear; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; C089969:snf protein, Drosophila; D011065:Poly(ADP-ribose) Polymerases