MOSAIC TRANSCRIPTS IN TRYPANOSOMA (NANNOMONAS) CONGOLENSE

The study of transcription in the Trypanosomatidae has revealed intric ate patterns of transcript processing and modifications in these micro -organisms. In the African trypanosomes, all the mRNA molecules posses s at their extreme 5' end a defined 39-nucleotide sequence designated the miniexon, that is added in trans post-synthesis. We have identifie d two different complementary DNA (cDNA) clones which contain the tran scripts of a Trypanosoma congolense gene that is transcribed specifica lly in the bloodstream form of the parasite, irrespective of the varia ble surface glycoprotein (VSG) expressed. Each of the cDNAs is compose d of transcripts that originate from at least two different genomic lo ci, one of which has a DNAaseI sensitive chromatin structure. The DNAa sel sensitive locus donates at least 200 nucleotides of each transcrip t. Neither locus is linked with any of three different VSG genes, wher e such a linkage has been investigated. Initial characterization of th e genes and their transcripts is presented.