Poster abstracts

Poster number 88 submitted by Annie Urban

Investigating the role of bS21 paralogs in Agrobacterium fabrum

Annie Urban (OSU Microbiology Department, Center for RNA Biology), Fawwaz Naeem (OSU Biochemistry Program, Center for RNA Biology), Yaowen Deng (OSU Biophysics Program, Center for RNA Biology), Ralf Bundschuh (Center for RNA Biology, OSU Biophysics program, OSU Department of Physics), Kurt Fredrick (OSu Microbiology Department, Center for RNA Biology, OSU Biophysics program)

Abstract:
Ribosomal protein bS21 forms part of the mRNA binding channel of the small (30S) subunit of the bacterial ribosome. bS21 lies near the anti-Shine-Dalgarno (ASD) sequence of 16S rRNA and can influence mRNA-rRNA base pairing during initiation in E. coli. bS21 is essential in some species, encoded by two or more paralogous genes in some species, and absent from other species (1). Recently, it was shown that production of bS21 is autoregulated in Flavobacterium johnsoniae by ribosomes lacking bS21 (2). Interestingly, bS21 is the most common phage-encoded ribosomal protein, and it has been suggested that incorporation of phage bS21 into host ribosomes can perturb protein synthesis during late-stage infection (3,4).
In Agrobacterium fabrum, there are three different rpsU (bS21) genes, denoted here as rpsU-A, rpsU-B, and rpsU-C. Based on gene neighborhood analysis, rpsU-A appears to be the ancestral gene. Analysis of RNA-seq data from various prior studies suggests that these three genes are differentially regulated. In this work, we have made precise allelic replacements to elucidate the roles of these rpsU genes. Deletion of rpsU-A causes a very severe growth defect, indicating the functional importance of this gene. Deletion of rpsU-C slightly enhances growth in minimal media, whereas rpsU-B modestly reduces growth in rich media. In the context of rpsU-B rpsU-C, the coding region of rpsU-A was replaced with that of rpsU-B, rpsU-C, or each of three phage-encoded bS21 genes. These strains exhibit variable growth rates, with larger defects seen for stains harboring phage bS21. Currently, we are performing ribosome profiling on these various strains. The data should reveal how bS21 paralogs can influence translation in the bacterial cell.

References:
1) Yutin et al. 2012
2)McNutt et al. 2023
3)Chen et al. 2022
4) Mizuno et al. 2019
5)Gonzalez-Mula et al.
6)Budnick et al. 2020
7)Eisfeld et al. 2021
8)Kraus et al. 2020
9)Jin et al. 2022

Keywords: S21, Agrobacterium, Initiation