title: Molecular genetic analysis of an SNF2/brahma-related gene in Tetrahymena thermophila suggests roles in growth and nuclear development.
abstract: We used a reverse genetic approach to identify three members of the SNF2 superfamily of chromatin remodeling genes in the ciliated protozoan Tetrahymena thermophila in order to investigate possible functions of ATP-dependent chromatin remodeling factors in growth and nuclear development. Comparative sequence analysis of the gene product of the Tetrahymena brahma-related gene (TtBRG1) indicates it is a member of the SNF2/BRM subgroup of the SNF2 superfamily. Northern analysis suggests that TtBRG1 has roles in growth and nuclear development in Tetrahymena. Indirect immunofluorescence analysis during nuclear development indicates that TtBrg1p localizes to both the parental and developing macronucleus of Tetrahymena during the time period corresponding to genome rearrangements. We generated germ line knockout heterokaryons for TtBRG1 and demonstrated that expression of the gene is required to complete nuclear development of Tetrahymena. In addition, the formation of distinct Pdd1p-containing structures is disturbed during the late stages of conjugation in TtBRG1 germ line knockout heterokaryons. We discuss these results in light of possible roles of SNF2-related proteins in growth and nuclear development of Tetrahymena.
authors.affiliation: Department of Biology, York University, 4700 Keele St, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Fillingham
authors.forename: Jyoti
authors.initials: J
authors.lastname: Garg
authors.forename: Nora
authors.initials: N
authors.lastname: Tsao
authors.forename: Nama
authors.initials: N
authors.lastname: Vythilingum
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Pearlman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D016808:Tetrahymena thermophila / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D015800:Protozoan Proteins; C516718:TtBRG1 protein, Tetrahymena thermophila