Transcription of Leishmania major Friedlin chromosome 1 initiates in both directions within a single region.
Almost nothing is known about the sequences involved in transcription initiation of protein-coding genes in the parasite Leishmania. We describe here the transcriptional analysis of chromosome 1 (chr1) from Leishmania major Friedlin (LmjF) which encodes the first 29 genes on one DNA strand, and the remaining 50 on the opposite strand. Strand-specific nuclear run-on assays showed that a low level of nonspecific transcription probably takes place over the entire chromosome, but an approximately 10-fold higher level of coding strand-specific RNA polymerase II (Pol II)-mediated transcription initiates within the strand-switch region. 5' RACE studies localized the initiation sites to a <100 bp region. Transfection studies support the presence of a bidirectional promoter within the strand-switch region, but suggest that other factors are also involved in Pol II transcription. Thus, while in most eukaryotes each gene possesses its own promoter, a single region seems to drive the expression of the entire chr1 in LmjF.
Martínez-Calvillo
Santiago
S
Seattle Biomedical Research Institute, and Department of Pathobiology, University of Washington, Seattle, WA 98109, USA.
Yan
Shaofeng
S
Nguyen
Dan
D
Fox
Mark
M
Stuart
Kenneth
K
Myler
Peter J
PJ
D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics* / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000235:genetics* / Q000528:radiation effects; D005809:Genes, Regulator / Q000235:genetics / Q000528:radiation effects; D007891:Leishmania / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics* / Q000528:radiation effects; D012313:RNA / Q000096:biosynthesis* / Q000235:genetics; D012319:RNA Polymerase II / Q000235:genetics*; D022821:RNA Splice Sites / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics* / Q000528:radiation effects; D014466:Ultraviolet Rays
D022821:RNA Splice Sites; D012313:RNA; D012319:RNA Polymerase II