Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1990 Aug;42(1):1-12.
doi: 10.1016/0166-6851(90)90107-w.

Structure of a telomeric expression site for variant specific surface antigens in Trypanosoma brucei

M Crozatier  1 , L H Van der Ploeg, P J Johnson, J Gommers-Ampt, P Borst
Affiliations

Structure of a telomeric expression site for variant specific surface antigens in Trypanosoma brucei

M Crozatier et al. Mol Biochem Parasitol. 1990 Aug.

Abstract

We have studied the organization of the expression site, in which most chromosome-internal variant-specific surface glycoprotein (VSG) genes of Trypanosoma brucei strain 427 are expressed (the dominant expression site) and compared it to the previously characterized VSG 221 expression site. With the exception of a 500 bp segment and a VSG pseudogene, which are absent from the dominant expression site, overall all major sequence elements of the two sites are organized similarly, as judged from their relative mapping positions by UV inactivation of transcription. Transcription is insensitive to 1 mg alpha-amanitin per ml, a characteristic property of VSG gene expression sites analyzed thus far. The sequence elements of the dominant expression site include at least one other expressed gene of unknown function and homologues of at least two other open reading frames. The large internal duplication of the 60-kb 221 expression site appear to be missing from the dominant site, resulting in a shorter, 40-kb transcription unit. As judged from its relative sensitivity to UV inactivation of transcription, a subsidiary promoter, identified by other methods in the dominant expression site appears fully dependent for its activity on the promoter located 40 kb upstream of the VSG gene. We conclude that all VSG gene expression sites may be similarly organized as large polygenic transcription units.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

LinkOut - more resources