Journal of Microbiology

Journal Articles

Fus3 and Tpk2 protein kinases regulate the phosphorylation-dependent functions of RNA helicase Dhh1 in yeast mating and Ste12 protein expression: Jaehee Hwang , Daehee Jung , Jinmi Kim; J. Microbiol. 2022;60(8):843-848. Published online July 14, 2022; DOI: https://doi.org/10.1007/s12275-022-2213-x

Abstract: Decapping of mRNA is a key regulatory step for mRNA decay and translation. The RNA helicase, Dhh1, is known as a decapping activator and translation repressor in yeast Saccharomyces cerevisiae. Dhh1 also functions as a gene-specific positive regulator in the expression of Ste12, a mating-specific transcription factor. A previous study showed that the Nerminal phosphorylation of Dhh1 regulates its association with the mRNA-binding protein, Puf6, to affect the protein translation of Ste12. Here, we investigated the roles of the phosphorylated residues of Dhh1 in yeast mating process and Ste12 expression. The phospho-deficient mutation, DHH1- T10A, was associated with decreased diploid formation during mating and decreased level of the Ste12 protein in response to α-mating pheromone. A kinase overexpression analysis revealed that Ste12 protein expression was affected by overexpression of Fus3 MAP kinase or Tpk2 kinase. Tpk2 was shown to be responsible for phosphorylation of Dhh1 at Thr10. Our study shows that overexpression of Fus3 or Tpk2 alters the Dhh1-Puf6 protein interaction and thereby affects Ste12 protein expression.

H2 Metabolism revealed by metagenomic analysis of subglacial sediment from East Antarctica: Zhifeng Yang , Yu Zhang , Yongxin Lv , Wenkai Yan , Xiang Xiao , Bo Sun , Hongmei Ma; J. Microbiol. 2019;57(12):1095-1104. Published online November 22, 2019; DOI: https://doi.org/10.1007/s12275-019-9366-2

Abstract: Subglacial ecosystems harbor diverse chemoautotrophic microbial communities in areas with limited organic carbon, and lithological H2 produced during glacial erosion has been considered an important energy source in these ecosystems. To verify the H2-utilizing potential there and to identify the related energy-converting metabolic mechanisms of these communities, we performed metagenomic analysis on subglacial sediment samples from East Antarctica with and without H2 supplementation. Genes coding for several [NiFe]- hydrogenases were identified in raw sediment and were enriched after H2 incubation. All genes in the dissimilatory nitrate reduction and denitrification pathways were detected in the subglacial community, and the genes coding for these pathways became enriched after H2 was supplied. Similarly, genes transcribing key enzymes in the Calvin cycle were detected in raw sediment and were also enriched. Moreover, key genes involved in H2 oxidization, nitrate reduction, oxidative phosphorylation, and the Calvin cycle were identified within one metagenome-assembled genome belonging to a Polaromonas sp. As suggested by our results, the microbial community in the subglacial environment we investigated consisted of chemoautotrophic populations supported by H2 oxidation. These results further confirm the importance of H2 in the cryosphere.

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