Post-transciptional Regulation of Cystathionine γ-synthase: Analyzing the Role of the Ribosomal Exit Tunnel

Abstract

Cystationine gamma-synthase (CGS) of Arabidopsis catalyzes the key step of methionine biosynthesis. Expression of the CGS1 gene is negatively feedback-regulated at the step of mRNA stability in response to S-adenosyl-L-methionine (SAM). CGS1 encodes a fourteen amino acid sequence (MTO1 region) in exon1, which is required for this regulation. When the ribosome is arrested on CGS1 mRNA, the nascent MTO1 peptide is predicted to be located within the ribosomal exit tunnel. We are currently analyzing the relationship between the ribosomal exit tunnel and CGS1 translation arrest.