Poster abstracts

Poster number 45 submitted by Duc Phan

Investigating RNase P-mediated 3′-maturation of MALAT1 and NEAT1, two long non-coding RNAs up-regulated in cancer

Duc Phan (Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State Biochemistry Program), James Li (Department of Chemistry and Biochemistry, Center for RNA Biology), Venkat Gopalan (Venkat Gopalan)

Abstract:
Long non-coding RNAs (lncRNAs) are > 200 nt in length and play important roles in controlling gene expression, cell cycle, and cell differentiation. Dysregulation of lncRNAs leads to many diseases. For instance, Metastasis- Associated Lung Adenocarcinoma Transcript 1 (MALAT1) and Nuclear Paraspeckle Assembly Transcript 1 (NEAT1) are up-regulated in different cancers and are potential therapeutic oncotargets. MALAT1 and NEAT1 precursors possess a tRNA-like structure at their 3′-termini. This structure is trimmed by RNase P, an essential enzyme that primarily catalyzes tRNA 5′-maturation, in order for the formation of mature MALAT1 and NEAT1. RNase P is a ribonucleoprotein with remarkable structural diversity. It comprises a catalytic RNA (RNase P RNA; RPR) and a variable number of protein cofactors (RNase P protein; RPP): one in Bacteria, up to five in Archaea, and up to ten in Eukarya. My study focuses on evaluating the functional role of each RPP in eukaryotic RNase P for processing pre-tRNA and non-tRNA substrates (e.g., MALAT1, NEAT1). My preliminary studies using partially purified native RNase P from mouse brains showed unexpectedly that increased purity (and concomitant loss of peripheral RPPs) resulted in a disproportionate decrease in processing of pre-lncRNAs compared to pre-tRNAs. To identify which RPP components are critical for lncRNA biogenesis, we are employing two different approaches: first, western blot and proteomics to pinpoint which component(s) is/are lost during the sequential purification of mouse RNase P and that compromise processing of lncRNAs; second, using the recombinant human RPPs purified from Escherichia coli, we are reconstituting the human RNase P in vitro to dissect the function of each RPP for both pre-tRNA and lncRNA maturation.

Keywords: RNase P, MALAT1, NEAT1