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Processing of mitochondrial RNA in Aspergillus nidulans
N J Dyson1, T A Brown, J A Ray
1Department of Biochemistry and Applied Molecular Biology, University of Manchester, U.K.
Journal of Molecular Biology
|August 20, 1989
Summary
Aspergillus nidulans mitochondrial transcription yields abundant RNAs from four genes. These abundant RNAs are processed from a limited number of primary transcripts, similar to metazoa.
Area of Science:
- Mitochondrial genetics
- Molecular biology
- Fungal genomics
Background:
- The Aspergillus nidulans mitochondrial genome contains genes for cytochrome oxidase subunits I and II (oxiA, oxiB), ATPase subunit 9, and NADH dehydrogenase subunit 3 (ndhC) within a 7.2 kb region.
- Understanding gene expression and RNA processing in fungal mitochondria is crucial for comparative genomics.
Purpose of the Study:
- To investigate the transcription and processing of mitochondrial genes in Aspergillus nidulans.
- To elucidate the mechanisms of RNA maturation from primary transcripts.
Main Methods:
- Northern hybridization to analyze RNA transcripts.
- S1 nuclease analysis to determine transcript termini and intron presence.
- Analysis of a specific 7.2 kb mitochondrial DNA segment.
Main Results:
- Abundant RNA molecules of 4.0, 2.5, and 1.5 kb are transcribed from the studied region.
- A 4.0 kb primary transcript containing all four genes is processed into smaller RNAs.
- Processing involves cleavage and potentially tRNA excision, yielding mature RNAs with staggered 5' termini.
Conclusions:
- Mitochondrial transcription in A. nidulans involves a limited number of primary transcripts.
- Extensive RNA processing, including tRNA excision, generates mature RNAs.
- RNA synthesis and processing pathways resemble those in metazoa, distinct from yeast.