Dynein Light Chain LC8 Is Required for RNA Polymerase I-Mediated Transcription in Trypanosoma brucei, Facilitating Assembly and Promoter Binding of Class I Transcription Factor A

摘要: Dynein light chain LC8 is highly conserved among eukaryotes and has both dynein-dependent dynein-independent functions. Interestingly, was identified as a subunit of the class I transcription factor A (CITFA), which essential for by RNA polymerase (Pol I) in parasite Trypanosoma brucei. Given that never been with basal T. brucei relies on Pol expressing variant surface glycoprotein (VSG), key protein antigenic variation, we investigated CITFA-specific role LC8. Depletion from mammalian-infective bloodstream trypanosomes affected cell cycle progression, reduced abundances rRNA VSG mRNA, resulted rapid death. Sedimentation analysis, coimmunoprecipitation recombinant proteins, bioinformatic analysis revealed an binding site near N terminus CITFA2. Mutation this prevented formation CITFA2-LC8 heterotetramer and, vivo, lethal, affecting assembly functional CITFA complex. Gel shift assays UV cross-linking experiments CITFA2 promoter-binding subunit. Accordingly, silencing or loss promoters. Hence, discovered interaction that, unprecedentedly, function transcription.