Proteomic and transcriptomic analysis of selenium utilization in Methanococcus maripaludis

Area of Science:

• Microbiology and Biochemistry
• Trace Element Metabolism
• Gene Regulation

Background:

• Methanococcus maripaludis uses selenocysteine (Sec) for energy metabolism, switching to cysteine (Cys) during selenium depletion.
• Previous studies focused on specific selenium pathways, lacking a global view of gene expression changes.
• Understanding microbial selenium utilization is crucial due to its environmental interconversion.

Purpose of the Study:

• To investigate the global gene expression response of M. maripaludis to varying selenium levels.
• To identify novel selenium sources utilized by M. maripaludis.
• To explore the function of putative selenium transporter genes.

Main Methods:

• Transcriptomic and proteomic analyses to assess differential gene and protein expression.
• Reporter strain assays to test utilization of various environmental selenium species.
• Loss-of-function mutagenesis of putative transporter genes.

Main Results:

• Approximately 7-12% of M. maripaludis genes/proteins showed altered expression in response to selenium.
• New selenium sources, including selenite and dimethylselenide, were confirmed, and others were evaluated.
• Mutagenesis of five putative transporters did not reveal essential roles in selenium utilization, suggesting redundancy.

Conclusions:

• Selenium status significantly impacts M. maripaludis gene expression, affecting metabolism and transport.
• The organism can utilize a broader range of selenium sources than previously known.
• The identified putative transporters likely have overlapping functions or are not solely dedicated to selenium uptake.