2006 Rustbelt RNA Meeting
RRM

Registration

Home

Abstracts

Directions

Poster abstracts

Poster number 18 submitted by Sunaina Yadav

Investigating the role of Mpp10p in ribosome biogenesis

Sunaina Yadav (Rosalind Franklin University of Medicine & Science, Dept. of Biochemistry and Molecular Biology), Timea Gerczei (Rosalind Franklin University of Medicine & Science, Dept. of Biochemistry and Molecular Biology), Carl C. Correll (Rosalind Franklin University of Medicine & Science, Dept. of Biochemistry and Molecular Biology)

Abstract:
Mpp10p is a target of autoantibodies produced in the human autoimmune disease systemic sclerosis. This essential protein is part of the small subunit (SSU) processome that initiates SSU biogenesis by releasing the 20S SSU precursor from the pre-rRNA via three endonucleolytic cleavages. In Saccharomyces cerevisiae, the model system for our studies, this processome contains approximately 39 other proteins and the U3 small nucleolar RNA (snoRNA). The role of most SSU processome proteins is unclear. Our studies aim to decipher the role of three processome proteins: Mpp10p and two of its interacting partners Imp3p and Imp4p. Previously, we determined that Imp3p and Imp4p mediate annealing between two specific sites of the U3 snoRNA and two complementary sites of the pre-rRNA (Gerczei and Correll (2004) PNAS 101, 15301). The annealing activities of Imp3p and Imp4p permit rapid and complete U3-pre-rRNA hybridization by removing kinetic and thermodynamic barriers. Here, we present the first biochemical evidence of direct interaction between Mpp10p and the U3 snoRNA. Foot printing studies indicate that Mpp10p binds specifically to the U3 snoRNA (Kd ~200 nM). The regions protected by Mpp10p include nucleotides in box B, box CĄŻ and the hinge region previously identified as essential for the association of Mpp10p with the SSU processome (Wormsley et al (2001) RNA 7, 904). Experiments are underway to determine how the presence of Mpp10p affects the U3-pre-rRNA annealing activities of Imp3p and Imp4p and to determine whether Mpp10p possesses inherent annealing activity.

Keywords: Ribosome biogenesis, Mpp10p, SSU processome