Trypanosoma brucei and other kinetoplastid protists possess a catenated network of mitochondrial DNA that consists of thousands of minicircles and several maxicircles. Maxicircles encode 18 mRNAs, 12 of which are referred to as cryptogenes whose transcripts must undergo uridine insertion/deletion editing for expression. Minicircle-encoded guide RNAs (gRNAs) provide information for the specific insertion and deletion of uridine nucleotides. Our lab is interested in the accessory proteins that, in addition to the editosome, which mediates the catalytic steps of kRNA editing, are required for the processivity and dynamics of the process. One essential multiprotein kRNA accessory factor is the MRB1 complex. A central part of the MRB1 complex are the GAP1 and GAP2 proteins that together form a GAP1/2 complex. The GAP1/GAP2 complex binds gRNAs and is required for their stability. In addition, GAP1/2 associates with protein complexes involved in RNA editing and other RNA processing events. However, the molecular mechanisms behind its gRNA binding activity and roles in RNA editing are not known. The proteins comprising the GAP complex are each ~50 kDa, show no sequence homology to any known protein and appear to form a heterotetramer. The goal of my project is to structurally and biochemically characterize GAP1/2 in order to elucidate its function in kRNA editing in atomic detail.
As Dr. Schumacher's right-hand man, Wenjie works tirelessly on many projects in the lab.
Hengshan "Steven" Zhang
Steven currently is involved in several projects in the lab including work on DNA segregation and transcription. He performs microscopy studies and is spearheading in vivo studies in the lab.