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Separable putative polyadenylation and cleavage motifs in Trichomonas vaginalis mRNAs
Norma Espinosa1, Roberto Hernández, Lorena López-Griego
1Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apartado Postal 70-228, 04510 Mexico D. F., Mexico.
Abstract:
3' Untranslated region processing and polyadenylation in Trichomonas vaginalis was analyzed by 3' rapid amplification of cDNA ends and sequence analysis of T. vaginalis mRNAs. A putative polyadenylation signal with the sequence UAAA was found 11-30 nucleotides upstream from the cleavage site. The motif pyrimidine( downward arrow)(A)(0-3)AAUU is proposed to be the cleavage site for polyadenylation of transcripts. This potential sequence defining the cleavage site for polyadenylation in eukaryotes is a novel finding. As in other eukaryotes, runs of several U's downstream from the cleavage site were identified. A working hypothesis is proposed which couples the UAA translation stop codon with the signaling for the 3'end processing of transcripts in this early divergent parasitic protozoa.