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A Drosophila third chromosome Minute locus encodes a ribosomal protein
S Andersson1, S Saebøe-Larssen, A Lambertsson
1Department of Genetics, University of Umeå, Sweden.
Abstract:
Minutes (M) are a group of over 50 phenotypically similar Drosophila mutations widely believed to affect ribosomal protein genes. This report describes the characterization of the P element-induced M(3)95A(Plac92) mutation [allelic to M(3)95A]. This mutation can be reversed by the mobilization of the P element, demonstrating that the mutation is caused by insertion of this transposable element. The gene interrupted by insertion of the P element was cloned by use of inverse polymerase chain reaction. Nucleotide sequence analysis revealed a 70-75% identity to the human and rat ribosomal protein S3 genes, and to the Xenopus ribosomal protein S1a gene. At the amino acid level, the overall identity is approximately 78% for all three species. This is only the second time that a Minute has been demonstrated to encode a ribosomal protein.
Insights
This study identifies a Drosophila mutation, M(3)95A, caused by P element insertion. The gene encodes a ribosomal protein, supporting the hypothesis that Minute mutations affect ribosomal protein genes.
Area of Science:
- Genetics
- Molecular Biology
- Developmental Biology
Background:
- Minute mutations in Drosophila melanogaster are numerous and phenotypically similar.
- These mutations are hypothesized to affect genes encoding ribosomal proteins.
- Previous research has identified only one Minute mutation linked to a ribosomal protein gene.
Purpose of the Study:
- To characterize the P element-induced M(3)95A mutation.
- To identify the gene affected by this specific Minute mutation.
- To determine if the affected gene encodes a ribosomal protein.
Main Methods:
- Characterization of P element-induced mutations.
- Mobilization of P elements to assess mutation reversibility.
- Inverse polymerase chain reaction for gene cloning.
- Nucleotide sequence analysis for gene identification and homology.
Main Results:
- The M(3)95A mutation was reversible upon P element mobilization, confirming P element insertion as the cause.
- The interrupted gene was cloned and sequenced.
- Sequence analysis showed significant homology (70-75% nucleotide identity, ~78% amino acid identity) to known ribosomal protein genes in humans, rats, and Xenopus.
- This represents the second instance of a Minute mutation being identified as a ribosomal protein gene.
Conclusions:
- The M(3)95A mutation is caused by P element insertion disrupting a ribosomal protein gene.
- This finding strengthens the hypothesis that many Minute mutations affect ribosomal protein genes.
- The study contributes to understanding gene function and mutation mechanisms in Drosophila.