Apparent generation of a segmented mRNA from two separate tandem gene families in Trypanosoma cruzi

Antonio Gonzalez, Terry J. Lerner, Maria Huecas, Beatriz Sosa-Pineda, Nadia Nogueira, Paul M. Lizardi*

*Corresponding author for this work

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

Using a cDNA for an abundant Trypanosoma cruzi mRNA as probe, we have cloned and sequenced a gene which is organized in at least 20 nearly perfect tandem repeats of 940 base pairs. The 5′ end of the mRNA has been sequenced by primer extension and found to containa 35 nucleotide mini-exon (or spliced-leader) sequence that is ubiquitous in trypanosome mRNAs. This sequence, however, is not present in the tandem genomic repeats which encode the exon containing the major portion of the mRNA. Previous studies have shown that the 35-nucleotide sequence is encoded by a separate tandem gene family. One model to explainthe formation of a segmented mRNA invokes priming of transcription by a small RNA which contains the leader sequence at its 5′ end. However, northern blot analysis of total trypanosome RNA reveals a ladder of molecules larger than the mature mRNA, which appear to be faithful multimeric copies of the tandem gene. The discrete sizes of these RNAs correspond to those expected for partially processed precursors. These observations lend credence to the possibility of an alternative model where segmented mRNAs are generated by inter-molecular splicing.

Original languageEnglish (US)
Pages (from-to)5789-5804
Number of pages16
JournalNucleic acids research
Volume13
Issue number16
DOIs
StatePublished - Aug 26 1985

ASJC Scopus subject areas

  • Genetics

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