Shahad Al-jarah | 2025 I.S Symposium

Name: Shahad Al-jarah
Title: Does Arginine Kinase Bias the Switch? Examining if an Arginine Kinase Deletion Impacts Successful Fruiting Body Formation in Tan and Yellow Phase Changing Myxococcus xanthus
Major: Biochemistry and Molecular Biology
Minors: Chinese Studies
Advisors: Dean Fraga

Previous investigations into the function of Arginine Kinase (AK) in Myxococcus xanthus depict knockout strains (dAK) have impaired recovery against environmental stressors including starvation induced sporulation. The phenomenon of phase switching between tan and yellow colonies within M. xanthus was found to similarly impact sporulation leading to asymmetric and diffuse fruiting bodies (FBs). As dAK strains were found to flip to tan phase more readily, we proposed the analysis of dAK’s impact on FB formation alongside the characterized mechanism of phase switching to understand AK’s role and significance in vivo.
Specifically, WT and dAK samples were examined alongside WT0228 and dAK0228 that are locked in the tan phase due to a deletion in a helix-turn-helix transcriptional regulator gene (MXAN_0228). The rate of phase switching was found to increase within dAK strains that had a larger tan colony percentage- indicating AK’s role in phase switching. As for FB formation, both the ∆AK and ∆AK0228 double knockouts depict a lag in development with significant variation amongst samples ranging from diffuse aggregation to partially rescued WT phenotypes. RNA sequencing data of dAK samples with opposing phenotypes depict regulation of phase associated genes, protein kinases, and TFs enable the variability among phenotypes. These findings suggest AK’s switch-like role in phase variability, with data supporting a putative model in which an AK loss favors the tan phase due to its survival advantage in non-stress conditions that upon starvation is reversed to enable yellow phase complementation that provides the rescued phenotype due to synergism amongst colonies.

Posted in Symposium 2025 on May 1, 2025.