This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Davis, R E Articles by Rottman, F M Search for Related Content PubMed PubMed Citation Articles by Davis, R E Articles by Rottman, F M

Tandemly repeated exons encode 81-base repeats in multiple, developmentally regulated Schistosoma mansoni transcripts.

Department of Molecular Biology and Microbiology, School of Medicine, University Hospital, Case Western Reserve University, Cleveland, Ohio 44106.

ABSTRACT

The adult Schistosoma mansoni cDNA clone 10-3 encodes an antigen that is recognized by sera from infected humans. We characterized multiple developmentally regulated transcripts homologous to the 10-3 cDNA and portions of the complex genomic loci encoding those transcripts. Transcripts of approximately 950, 870, and 780 nucleotides were expressed in adults, whereas only the 780-nucleotide transcript was observed in the larval stage. These transcripts were highly similar, containing variable numbers of identical direct tandem repeats of 81 bases. Although the sequence of the repeating elements and sequences 3' to them were identical in all the transcripts, sequences 5' of the repeating elements exhibited variations, including a 27-base insertion, alternative start sites for transcription, and alternate 5' exon usage. These transcripts appeared to be derived in part by the developmentally controlled alternative splicing of small exons and the use of alternative transcription initiation sites from the one or two complex loci of at least 40 kilobase pairs. Each 81-base repeat in the transcripts was encoded by three dispersed 27-base-pair exons. These 27-base-pair exons were contained within highly conserved, reiterated 3-kilobase-pair genomic tandem arrays.

This article has been cited by other articles:

• Davis, R. E., Hardwick, C., Tavernier, P., Hodgson, S., Singh, H. (1995). RNA Trans-splicing in Flatworms. J. Biol. Chem. 270: 21813-21819 [Abstract] [Full Text]