title: TRF4 is involved in polyadenylation of snRNAs in Drosophila melanogaster.
abstract: The Saccharomyces cerevisiae poly(A) polymerases Trf4 and Trf5 are involved in an RNA quality control mechanism, where polyadenylated RNAs are degraded by the nuclear exosome. Although Trf4/5 homologue genes are distributed throughout multicellular organisms, their biological roles remain to be elucidated. We isolated here the two homologues of Trf4/5 in Drosophila melanogaster, named DmTRF4-1 and DmTRF4-2, and investigated their biological function. DmTRF4-1 displayed poly(A) polymerase activity in vitro, whereas DmTRF4-2 did not. Gene knockdown of DmTRF4-1 by RNA interference is lethal in flies, as is the case for the trf4 trf5 double mutants. In contrast, disruption of DmTRF4-2 results in viable flies. Cellular localization analysis suggested that DmTRF4-1 localizes in the nucleolus. Abnormal polyadenylation of snRNAs was observed in transgenic flies overexpressing DmTRF4-1 and was slightly increased by the suppression of DmRrp6, the 3'-5' exonuclease of the nuclear exosome. These results suggest that DmTRF4-1 and DmRrp6 are involved in the polyadenylation-mediated degradation of snRNAs in vivo.
authors.affiliation: Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda-shi Chiba-ken, 278-8510, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Nakamura
authors.forename: Ryo
authors.initials: R
authors.lastname: Takeuchi
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Takata
authors.forename: Kaori
authors.initials: K
authors.lastname: Shimanouchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Abe
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kanai
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Ruike
authors.forename: Ayumi
authors.initials: A
authors.lastname: Ihara
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi