Control of variant surface glycoprotein gene-expression sites in Trypanosoma brucei
- PMID: 10469662
- PMCID: PMC1171556
- DOI: 10.1093/emboj/18.17.4846
Control of variant surface glycoprotein gene-expression sites in Trypanosoma brucei
Abstract
Trypanosoma brucei has 20 similar telomeric-expression sites for variant surface glycoprotein genes. Expression sites appear to be controlled at the level of transcription initiation, resulting in only one site being active at any time. Switching between expression sites occurs at a low rate. To analyse the switching mechanism, we used trypanosomes with two expression sites tagged with two different drug-resistance genes and selected these on agarose plates containing both drugs. Double-resistant clones arose at a low frequency of 10(-7) per cell, but these behaved as if they rapidly switched between the two tagged expression sites and lost double resistance in the absence of selection. Using in situ hybridization we found that only 10% of the double-resistant cells had two fluorescent spots corresponding to transcribed expression sites. Our results suggest that: (i) a double expressor is not a stable intermediate in expression site switching; (ii) expression sites are not independently switched on and off; and (iii) expression sites can be in a 'pre-active' silent state from which they can be readily activated.
Similar articles
-
Selection for activation of a new variant surface glycoprotein gene expression site in Trypanosoma brucei can result in deletion of the old one.Mol Biochem Parasitol. 1998 Sep 1;95(1):97-109. doi: 10.1016/s0166-6851(98)00099-1. Mol Biochem Parasitol. 1998. PMID: 9763292
-
Telomere exchange can be an important mechanism of variant surface glycoprotein gene switching in Trypanosoma brucei.Mol Biochem Parasitol. 1996 Sep;80(1):65-75. doi: 10.1016/0166-6851(96)02669-2. Mol Biochem Parasitol. 1996. PMID: 8885223
-
Expression site activation in Trypanosoma brucei with three marked variant surface glycoprotein gene expression sites.Mol Biochem Parasitol. 2002 Apr 9;120(2):225-35. doi: 10.1016/s0166-6851(02)00003-8. Mol Biochem Parasitol. 2002. PMID: 11897128
-
Control of VSG gene expression sites.Mol Biochem Parasitol. 2001 Apr 25;114(1):17-27. doi: 10.1016/s0166-6851(01)00243-2. Mol Biochem Parasitol. 2001. PMID: 11356510 Review.
-
Mechanisms of antigenic variation in African trypanosomes.Behring Inst Mitt. 1997 Mar;(99):1-15. Behring Inst Mitt. 1997. PMID: 9303197 Review.
Cited by
-
The central roles of telomeres and subtelomeres in antigenic variation in African trypanosomes.Chromosome Res. 2005;13(5):525-33. doi: 10.1007/s10577-005-0991-8. Chromosome Res. 2005. PMID: 16132817 Review.
-
Active VSG expression sites in Trypanosoma brucei are depleted of nucleosomes.Eukaryot Cell. 2010 Jan;9(1):136-47. doi: 10.1128/EC.00281-09. Epub 2009 Nov 13. Eukaryot Cell. 2010. PMID: 19915073 Free PMC article.
-
Trypanosoma brucei ATR Links DNA Damage Signaling during Antigenic Variation with Regulation of RNA Polymerase I-Transcribed Surface Antigens.Cell Rep. 2020 Jan 21;30(3):836-851.e5. doi: 10.1016/j.celrep.2019.12.049. Cell Rep. 2020. PMID: 31968257 Free PMC article.
-
A novel ISWI is involved in VSG expression site downregulation in African trypanosomes.EMBO J. 2007 May 2;26(9):2400-10. doi: 10.1038/sj.emboj.7601678. Epub 2007 Apr 12. EMBO J. 2007. PMID: 17431399 Free PMC article.
-
Cell biology of the trypanosome genome.Microbiol Mol Biol Rev. 2010 Dec;74(4):552-69. doi: 10.1128/MMBR.00024-10. Microbiol Mol Biol Rev. 2010. PMID: 21119017 Free PMC article. Review.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
