Mutations in the hrp48 gene, which encodes a Drosophila heterogeneous nuclear ribonucleoprotein particle protein, cause lethality and developmental defects and affect P-element third-intron splicing in vivo
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L E Hammond1, D Z Rudner, R Kanaar
1Department of Molecular and Cell Biology, University of California, Berkeley 94720-3202, USA.
Abstract:
The Drosophila melanogaster hnRNP protein, hrp48, is an abundant heterogeneous nuclear RNA-associated protein. Previous biochemical studies have implicated hrp48 as a component of a ribonucleoprotein complex involved in the regulation of the tissue-specific alternative splicing of the P-element third intron (IVS3). We have taken a genetic approach to analyzing the role of hrp48. Mutations in the hrp48 gene were identified and characterized. hrp48 is an essential gene. Hypomorphic mutations which reduce the level of hrp48 protein display developmental defects, including reduced numbers of ommatidia in the eye and morphological bristle abnormalities. Using a P-element third-intron reporter transgene, we found that reduced levels of hrp48 partially relieve IVS3 splicing inhibition in somatic cells. This is the first direct evidence that hrp48 plays a functional role in IVS3 splicing inhibition.
Insights
The heterogeneous nuclear ribonucleoprotein (hnRNP) hrp48 is essential in Drosophila development. Genetic analysis reveals hrp48
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- The Drosophila melanogaster hnRNP protein, hrp48, is abundant and associated with heterogeneous nuclear RNA.
- Biochemical studies suggest hrp48's role in a ribonucleoprotein complex regulating tissue-specific alternative splicing of the P-element third intron (IVS3).
Purpose of the Study:
- To genetically analyze the function of the hrp48 gene in Drosophila melanogaster.
- To investigate hrp48's role in P-element third intron (IVS3) splicing regulation.
Main Methods:
- Identification and characterization of mutations in the hrp48 gene.
- Analysis of developmental defects in flies with reduced hrp48 protein levels.
- Utilizing a P-element third-intron reporter transgene to assess splicing inhibition.
Main Results:
- hrp48 is identified as an essential gene in Drosophila.
- Hypomorphic mutations leading to reduced hrp48 protein levels cause developmental defects, including eye and bristle abnormalities.
- Reduced hrp48 levels partially alleviate IVS3 splicing inhibition in somatic cells.
Conclusions:
- This study provides the first direct genetic evidence for hrp48's functional role in IVS3 splicing inhibition.
- hrp48 plays a critical role in regulating alternative splicing during Drosophila development.