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SUMMARY:From tagging to transcription activation in trypanosomes - Dr Jack
  Sunter
DTSTART:20220302T160000Z
DTEND:20220302T170000Z
UID:TALK165544@talks.cam.ac.uk
CONTACT:Anna Protasio
DESCRIPTION:Monoallelic expression of a single gene family member underpin
 s a molecular “arms race” between many pathogens and their host\, thro
 ugh host monoallelic immunoglobulin and pathogen monoallelic antigen expre
 ssion. In Trypanosoma brucei\, a single\, abundant\, variant surface glyco
 protein (VSG) covers the entire surface of the bloodstream parasite and mo
 noallelic VSG transcription underpins their archetypal example of antigeni
 c variation. It is vital for pathogenicity\, only occurring in mammalian i
 nfectious forms. Transcription of one VSG gene is achieved by RNA polymera
 se I (Pol I) in a singular nuclear structure: the expression site body (ES
 B). How monoallelic expression of the single VSG is achieved is incomplete
 ly understood and no specific ESB components are known. Here\, using a pro
 tein localisation screen in bloodstream parasites\, we discovered the firs
 t ESB-specific protein: ESB1. It is specific to VSG-expressing life cycle 
 stages where it associates with DNA near the 12 active promoter\, is neces
 sary for VSG expression\, and its overexpression activates inactive VSG pr
 omoters. This showed monoallelic VSG transcription requires a stage-specif
 ic transcription activator. Furthermore\, ESB1 is necessary for Pol I recr
 uitment to the ESB\, while transcript processing and inactive VSG gene exc
 lusion ESB sub-domains do not require ESB1. This shows that the cellular s
 olution for monoallelic transcription is a complex factory of functionally
  distinct and separably assembled sub-domains.\n\nThis talk will be broadc
 asted via Zoom. Please use this "link":https://zoom.us/j/95026514738?pwd=a
 Utoam1zbDRYYWU0M1Nob2VPQXNvZz09 to gain access. 
LOCATION:Thomas Lecture Theatre\, Dept. of Biochemistry (Sanger)
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