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Cloning the human and mouse MMS19 genes and functional complementation of a yeast mms19 deletion mutant
L Queimado1, M Rao, R A Schultz
1Laboratory of Molecular Pathology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9072, USA.
Abstract:
The MMS19 gene of the yeast Saccharomyces cerevisiae encodes a polypeptide of unknown function which is required for both nucleotide excision repair (NER) and RNA polymerase II (RNAP II) transcription. Here we report the molecular cloning of human and mouse orthologs of the yeast MMS19 gene. Both human and Drosophila MMS19 cDNAs correct thermosensitive growth and sensitivity to killing by UV radiation in a yeast mutant deleted for the MMS19 gene, indicating functional conservation between the yeast and mammalian gene products. Alignment of the translated sequences of MMS19 from multiple eukaryotes, including mouse and human, revealed the presence of several conserved regions, including a HEAT repeat domain near the C-terminus. The presence of HEAT repeats, coupled with functional complementation of yeast mutant phenotypes by the orthologous protein from higher eukaryotes, suggests a role of Mms19 protein in the assembly of a multiprotein complex(es) required for NER and RNAP II transcription. Both the mouse and human genes are ubiquitously expressed as multiple transcripts, some of which appear to derive from alternative splicing. The ratio of different transcripts varies in several different tissue types.
Insights
Human and mouse MMS19 genes are functionally conserved with yeast, playing a role in DNA repair and transcription. These findings suggest Mms19 protein involvement in crucial cellular complex assembly.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The MMS19 gene in yeast (Saccharomyces cerevisiae) encodes a protein with an unknown function.
- This protein is essential for both nucleotide excision repair (NER) and RNA polymerase II (RNAP II) transcription processes.
Purpose of the Study:
- To identify and characterize human and mouse orthologs of the yeast MMS19 gene.
- To investigate the functional conservation and potential role of Mms19 protein in higher eukaryotes.
Main Methods:
- Molecular cloning of human and mouse MMS19 genes.
- Functional complementation assays using a yeast MMS19 deletion mutant.
- Sequence alignment of MMS19 orthologs across different species.
Main Results:
- Human and Drosophila MMS19 cDNAs successfully corrected thermosensitive growth and UV sensitivity in yeast MMS19 mutants.
- Sequence analysis revealed conserved regions, including a HEAT repeat domain, in Mms19 proteins.
- Both mouse and human MMS19 genes are ubiquitously expressed, with alternative splicing generating multiple transcripts.
Conclusions:
- Mms19 protein function is conserved from yeast to mammals, indicating a vital role in essential cellular processes.
- The presence of HEAT repeats suggests Mms19 protein may be involved in assembling multiprotein complexes for NER and RNAP II transcription.
- Differential expression of MMS19 transcripts across tissues suggests complex regulatory mechanisms.