mRNA processing in Dictyostelium: sequence requirements for termination and splicing |
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Authors: | Rivero Francisco |
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Institution: | 1. Institut für Biochemie I, Medizinische Fakultät, University of Cologne, Joseph-Stelzmann-Straße 52, D-50931 Köln, Germany |
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Abstract: | Criteria for the identification of termination regions in Dictyostelium discoideum genes have been established and the sequence requirements for termination in 33 genes have been analyzed. A canonical hexamer signal AATAAA was present 15-30 nucleotides upstream of the cleavage site, usually a TA, and was embedded in a particularly A-rich environment. T- or GT-rich downstream elements characteristic of animal cells could not be identified. In a sample of 102 introns we have established the consensus AG/GTAAGT and ATAG/ for the 5' and 3' splice sites, respectively. Most introns are 75-150 nucleotides long and the A+T content is high (90%). A putative branch point was identified in half of the introns 20-60 nucleotides upstream of the 3' splice site and the consensus TACTAAY was derived. A polypyrimidine tract required for branching in vertebrates was not identified, but weak preference for pyrimidine was found 10-45 nucleotides upstream of the 3' splice site. |
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Keywords: | intron polyadenylation splicing terminator |
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