Control of VSG gene expression sites.
نویسندگان
چکیده
Trypanosoma brucei survives in mammals by antigenic variation of its surface coat consisting of variant surface glycoprotein (VSG). Trypanosomes change coat mainly by replacing the transcribed VSG genes in an active telomeric expression site by a different VSG gene. There are about 20 different expression sites and trypanosomes can also change coat by switching the site that is active. This review summarizes recent work on the mechanism of site switching and on the way inactive expression sites are kept silent.
منابع مشابه
Localization of the modified base J in telomeric VSG gene expression sites of Trypanosoma brucei.
African trypanosomes such as Trypanosoma brucei undergo antigenic variation in the bloodstream of their mammalian hosts by regularly changing the variant surface glycoprotein (VSG) gene expressed. The transcribed VSG gene is invariably located in a telomeric expression site. There are multiple expression sites and one way to change the VSG gene expressed is by activating a new site and inactiva...
متن کاملTranscription is initiated on silent variant surface glycoprotein expression sites despite monoallelic expression in Trypanosoma brucei.
African trypanosomes survive the immune defense of their hosts by regularly changing their antigenic coat made of variant surface glycoprotein (VSG). The Trypanosoma brucei genome contains more than 1,000 VSG genes. To be expressed, a given VSG gene must be located in one of 15 telomeric regions termed "VSG expression sites" (ESs), each of which contains a polycistronic transcription unit that ...
متن کاملA ribosomal DNA promoter replacing the promoter of a telomeric VSG gene expression site can be efficiently switched on and off in T. brucei
Trypanosoma brucei survives in the mammalian blood-stream by regularly changing its variant surface glycoprotein (VSG) coat. The active VSG gene is located in a telomeric expression site, and coat switching occurs either by replacing the transcribed VSG gene or by changing the expression site that is active. To determine whether VSG expression site control requires promoter-specific sequences, ...
متن کاملSwitching trypanosome coats: what's in the wardrobe?
The African trypanosome Trypanosoma brucei is best known for its extraordinarily sophisticated antigenic variation of a protective variant surface glycoprotein (VSG) coat. T. brucei has >1000 VSG genes and pseudogenes, of which one is transcribed at a time from one of multiple telomeric VSG expression sites. Switching the active VSG gene can involve DNA rearrangements replacing the old VSG with...
متن کاملMechanisms mediating antigenic variation in Trypanosoma brucei.
Antigenic variation in Trypanosoma brucei is a highly sophisticated survival strategy involving switching between the transcription of one of an estimated thousand variant surface glycoprotein (VSG) genes. Switching involves either transcriptional control, resulting in switching between different VSG expression sites; or DNA rearrangement events slotting previously inactive VSG genes into an ac...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Molecular and biochemical parasitology
دوره 114 1 شماره
صفحات -
تاریخ انتشار 2001