EurekaMag.com logo
+ Site Statistics
References:
53,869,633
Abstracts:
29,686,251
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

High-resolution analysis of multi-copy variant surface glycoprotein gene expression sites in African trypanosomes



High-resolution analysis of multi-copy variant surface glycoprotein gene expression sites in African trypanosomes



Bmc Genomics 17(1): 806-806



African trypanosomes cause lethal diseases in humans and animals and escape host immune attack by switching the expression of Variant Surface Glycoprotein (VSG) genes. The expressed VSGs are located at the ends of telomeric, polycistronic transcription units known as VSG expression sites (VSG-ESs). Each cell has many VSG-ESs but only one is transcribed in bloodstream-form parasites and all of them are inactive upon transmission to the insect vector mid-gut; a subset of monocistronic metacyclic VSG-ESs are then activated in the insect salivary gland. Deep-sequence analyses have been informative but assigning sequences to individual VSG-ESs has been challenging because they each contain closely related expression-site associated genes, or ESAGs, thought to contribute to virulence. We utilised ART, an in silico short read simulator to demonstrate the feasibility of accurately aligning reads to VSG-ESs. Then, using high-resolution transcriptomes from isogenic bloodstream and insect-stage Lister 427 Trypanosoma brucei, we uncover increased abundance in the insect mid-gut stage of mRNAs from metacyclic VSG-ESs and of mRNAs from the unusual ESAG, ESAG10. Further, we show that the silencing associated with allelic exclusion involves repression focussed at the ends of the VSG-ESs. We also use the approach to report relative fitness costs following ESAG RNAi from a genome-scale screen. By assigning sequences to individual VSG-ESs we provide new insights into VSG-ES transcription control, allelic exclusion and impacts on fitness. Thus, deeper insights into the expression and function of regulated multi-gene families are more accessible than previously anticipated.

(PDF emailed within 0-6 h: $19.90)

Accession: 057994752

Download citation: RISBibTeXText

PMID: 27756224

DOI: 10.1186/s12864-016-3154-8



Related references

Leaky transcription of variant surface glycoprotein gene expression sites in bloodstream african trypanosomes. Journal of Biological Chemistry 274(24): 16884-16893, 1999

Biological variation among african trypanosomes: I. Clonal expression of virulence is not linked to the variant surface glycoprotein or the variant surface glycoprotein gene telomeric expression site. Dna and Cell Biology 29(5): 215-227, 2010

Analysis of a donor gene region for a variant surface glycoprotein and its expression site in African trypanosomes. Nucleic Acids Research 29(10): 2012-2019, 2001

Co-duplication of a variant surface glycoprotein gene and its promoter to an expression site in African trypanosomes. Journal of Biological Chemistry 272(39): 24637-24645, 1997

Simultaneous transcription of 2 expression sites for variant surface glycoprotein genes in trypanosomes. Journal of Cellular Biochemistry Supplement (9 PART B): 163, 1985

Evolution of Antigenic Variation in African Trypanosomes: Variant Surface Glycoprotein Expression, Structure, and Function. Bioessays 1800181-E1800181, 2018

An expression-site-associated gene family of trypanosomes is expressed in vivo and shows homology to a variant surface glycoprotein gene. Molecular and Biochemical Parasitology 43.1: 1-16, 1990

Microbial surface elements: the case of variant surface glycoprotein (VSG) genes of African trypanosomes. Genetic engineering principles and methods(3): 129-155, 1981

The variant surface glycoprotein as a tool for adaptation in African trypanosomes. Microbes and Infection 8(3): 930-937, 2006

The inactivation and reactivation of an expression-linked gene copy for a variant surface glycoprotein in Trypanosoma brucei. Embo Journal 3(6): 1345-1351, 1984

Targeting the variable surface of African trypanosomes with variant surface glycoprotein-specific, serum-stable RNA aptamers. Eukaryotic Cell 2(1): 84-94, 2003

High homology between variant surface glycoprotein gene expression sites of Trypanosoma brucei and Trypanosoma gambiense. Molecular and Biochemical Parasitology 48.2: 199-210, 1991

Control of variant surface glycoprotein messenger rna synthesis in african trypanosomes. Journal of Cellular Biochemistry Supplement (13 PART E): 65, 1989

Maintaining the protective variant surface glycoprotein coat of African trypanosomes. Biochemical Society Transactions 33(Pt 5): 981-982, 2005

Characterization of t helper cell responses to the variant surface glycoprotein vsg of african trypanosomes. FASEB Journal 6(4): A1220, 1992