A Tetrahymena Piwi protein and the exonuclease Xrn2 form a complex that is essential for ribosome biogenesis

ABSTRACT: Emerging evidence suggests that Ago/Piwi proteins function in the nucleus as well as the cytoplasm to control gene expression, but the mechanisms they employ in the nucleus remain poorly defined. The Tetrahymena thermophila Ago/Piwi protein Twi12 is essential for growth and functions in the nucleus. We show that Twi12 interacts with the exonuclease Xrn2. Twi12 functions to stabilize and localize Xrn2 in vivo, as well as activate its exonuclease activity in vitro. When Twi12 or Xrn2 are depleted, pre-rRNA processing intermediates accumulate and mature rRNA levels decline. RNA polymerase I and II (RNAP I and II) transcripts also accumulate. Twi12 function depends on small RNA (sRNA) binding, which is required for its nuclear import. Twi12-bound sRNAs are Dicer-independent 3' tRNA fragments t

ORGANISM(S): Tetrahymena thermophila

SUBMITTER: Mary Couvillion 

PROVIDER: E-GEOD-38507 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress