Development of genetic methods and construction of a chromosomal glnK1 mutant in Methanosarcina mazei strain Gö1
| Autor: | Claudia Ehlers, Ruth A. Schmitz, Katharina Veit, Katrin Weidenbach, Uwe Deppenmeier, William W. Metcalf |
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| Rok vydání: | 2005 |
| Předmět: |
Plating efficiency
Chromosomes Archaeal Nitrogen assimilation Blotting Western Mutant Cell Culture Techniques Biology Escherichia coli Genetics Molecular Biology DNA Primers Strain (chemistry) Reverse Transcriptase Polymerase Chain Reaction Wild type General Medicine Culture Media Blotting Southern Transformation (genetics) Biochemistry Liposomes Methanosarcina Mutation Puromycin Transformation Bacterial Chromosome Deletion Energy source Homologous recombination |
| Zdroj: | Molecular Genetics and Genomics. 273:290-298 |
| ISSN: | 1617-4623 1617-4615 |
| Popis: | The methanogenic archaeon Methanosarcina mazei strain Gö1 has so far proven to be genetically intractable due to its low plating efficiency on solid medium and the lack of an effective transformation method. Here, we report the first significant improvement in plating efficiency (up to 10%), which was achieved by (1) selecting for a spontaneous mutant of M. mazei that shows significantly higher resistance to mechanical stress during spreading an agar plates, and (2) plating the cells in 0.5% top agar with trimethylamine as a carbon and energy source under a H2S-containing atmosphere (0.1%). Using this mutant we succeeded in establishing a liposome-mediated transformation protocol, which for the first time allowed genetic manipulation of the M. mazei Gö1 strain. We further report on the construction of the first chromosomal deletion mutant of M. mazei by means of homologous recombination. Characterization of this mutant strain revealed that M. mazei cells lacking a functional glnK1-gene exhibited a partial growth defect under nitrogen limitation when molecular nitrogen was used as the sole nitrogen source. Quantitative RT-PCR analysis, however, showed that genes involved in nitrogen assimilation or nitrogen fixation are transcribed in the glnK1 mutant as in the wild type. Thus, we propose that the archaeal GlnK1 protein is not directly involved in the transcriptional regulation of genes involved in nitrogen metabolism, but rather affects their protein products directly. |
| Databáze: | OpenAIRE |
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