sRNA‐pathway genes regulating myxobacterial development exhibit clade‐specific evolution

Chen, I‐Chen Kimberly; Satinsky, Brandon M.; Velicer, Gregory J.; Yu, Yuen‐Tsu Nicco

doi:10.1111/ede.12281

Cited by 2 publications

(1 citation statement)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, undergoing development while nutrients are still abundant would seem undesirable. Previous work from our group has identified several genes that regulate the transition to development, all of which appear to belong to the same regulatory pathway controlled by the small RNA Pxr ( Yu et al, 2010 , 2016 ; Chen et al, 2019 ). In this study, we identify a mutation in the universal bacterial transcription machinery gene rpoB that impacts the M. xanthus developmental response to nutrients, a connection not revealed by mutations previously known to confer RM development.…”

Section: Discussionmentioning

confidence: 99%

Mutation of rpoB Shifts the Nutrient Threshold Triggering Myxococcus Multicellular Development

Eisner

Velicer

2022

Front. Microbiol.

Self Cite

View full text Add to dashboard Cite

The ability to perceive and respond to environmental change is essential to all organisms. In response to nutrient depletion, cells of the soil-dwelling δ-proteobacterium Myxococcus xanthus undergo collective morphogenesis into multicellular fruiting bodies and transform into stress-resistant spores. This process is strictly regulated by gene networks that incorporate both inter- and intracellular signals. While commonly studied M. xanthus reference strains and some natural isolates undergo development only in nutrient-poor conditions, some lab mutants and other natural isolates commit to development at much higher nutrient levels, but mechanisms enabling such rich medium development remain elusive. Here we investigate the genetic basis of rich medium development in one mutant and find that a single amino acid change (S534L) in RpoB, the β-subunit of RNA polymerase, is responsible for the phenotype. Ectopic expression of the mutant rpoB allele was sufficient to induce nutrient-rich development. These results suggest that the universal bacterial transcription machinery bearing the altered β-subunit can relax regulation of developmental genes that are normally strictly controlled by the bacterial stringent response. Moreover, the mutation also pleiotropically mediates a tradeoff in fitness during vegetative growth between high vs. low nutrient conditions and generates resistance to exploitation by a developmental cheater. Our findings reveal a previously unknown connection between the universal transcription machinery and one of the most behaviorally complex responses to environmental stress found among bacteria.

show abstract

Section: Discussionmentioning

confidence: 99%

Mutation of rpoB Shifts the Nutrient Threshold Triggering Myxococcus Multicellular Development

Eisner

Velicer

2022

Front. Microbiol.

Self Cite

View full text Add to dashboard Cite

show abstract

Ribonuclease D Processes a Small RNA Regulator of Multicellular Development in Myxobacteria

Cossey

Velicer

2023

Genes

View full text Add to dashboard Cite

By targeting mRNA transcripts, non-coding small RNAs (sRNAs) regulate the expression of genes governing a wide range of bacterial functions. In the social myxobacterium Myxococcus xanthus, the sRNA Pxr serves as a gatekeeper of the regulatory pathway controlling the life-cycle transition from vegetative growth to multicellular fruiting body development. When nutrients are abundant, Pxr prevents the initiation of the developmental program, but Pxr-mediated inhibition is alleviated when cells starve. To identify genes essential for Pxr function, a developmentally defective strain in which Pxr-mediated blockage of development is constitutively active (strain “OC”) was transposon-mutagenized to identify suppressor mutations that inactivate or bypass Pxr inhibition and thereby restore development. One of the four loci in which a transposon insertion restored development is rnd, encoding the Ribonuclease D protein (RNase D). RNase D is an exonuclease important for tRNA maturation. Here, we show that disruption of rnd abolishes the accumulation of Pxr-S, the product of Pxr processing from a longer precursor form (Pxr-L) and the active inhibitor of development. Additionally, the decrease in Pxr-S caused by rnd disruption was associated with increased accumulation primarily of a longer novel Pxr-specific transcript (Pxr-XL) rather than of Pxr-L. The introduction of a plasmid expressing rnd reverted cells back to OC-like phenotypes in development and Pxr accumulation, indicating that a lack of RNase D alone suppresses the developmental defect of OC. Moreover, an in vitro Pxr-processing assay demonstrated that RNase D processes Pxr-XL into Pxr-L; this implies that overall, Pxr sRNA maturation requires a sequential two-step processing. Collectively, our results indicate that a housekeeping ribonuclease plays a central role in a model form of microbial aggregative development. To our knowledge, this is the first evidence implicating RNase D in sRNA processing.

show abstract

sRNA‐pathway genes regulating myxobacterial development exhibit clade‐specific evolution

Cited by 2 publications

References 66 publications

Mutation of rpoB Shifts the Nutrient Threshold Triggering Myxococcus Multicellular Development

Mutation of rpoB Shifts the Nutrient Threshold Triggering Myxococcus Multicellular Development

Ribonuclease D Processes a Small RNA Regulator of Multicellular Development in Myxobacteria

Contact Info

Product

Resources

About