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Polyomavirus early region alternative poly(A) site: 3'-end heterogeneity and altered splicing pattern
1Tumour Virus Genetics Laboratory, Imperial Cancer Research Fund, London, England.
Journal of Virology
|December 1, 1987
Summary
An alternative polyadenylation site in polyomavirus middle T antigen (T-Ag) affects gene regulation. This site
Area of Science:
- Molecular Biology
- Virology
- Gene Regulation
Background:
- Polyomavirus middle T antigen (T-Ag) coding sequences possess an alternative polyadenylation [poly(A)] site.
- The functional role of this alternative poly(A) site in early gene regulation is under investigation.
Purpose of the Study:
- To determine the fine structure of the alternative poly(A) site in polyomavirus.
- To analyze the impact of the alternative poly(A) site on mRNA splicing and T-Ag expression.
Main Methods:
- Complementary DNA (cDNA) sequencing.
- 3' S1 nuclease protection analyses.
- Analysis of mRNA splicing patterns.
Main Results:
- Cleavage and polyadenylation at the alternative site were heterogeneous, occurring at multiple CA dinucleotides downstream of the AATAAA signal.
- Approximately 50% of alternative polyadenylation occurred upstream of the middle T-Ag stop codon.
- Transcripts utilizing the alternative poly(A) site exhibited altered splicing patterns compared to those using the major poly(A) site.
Conclusions:
- The alternative poly(A) site and its associated heterogeneous 3'-end processing lead to altered mRNA splicing.
- This results in preferential translation of small T-Ag and middle T-Ag over large T-Ag during the polyomavirus lytic cycle.