TbPIF5 Is a Trypanosoma brucei Mitochondrial DNA Helicase Involved in Processing of Minicircle Okazaki Fragments

摘要: Trypanosoma brucei's mitochondrial genome, kinetoplast DNA (kDNA), is a giant network of catenated rings. The consists few thousand 1 kb minicircles and several dozen 23 maxicircles. Here we report that TbPIF5, one T. six proteins related to Saccharomyces cerevisiae helicase ScPIF1, involved in minicircle lagging strand synthesis. Like its yeast homolog, TbPIF5 5′ 3′ helicase. Together with other enzymes thought be Okazaki fragment processing, localizes vivo the antipodal sites flanking kDNA. Minicircles wild type cells replicate unidirectionally as theta-structures are unusual fragments not joined until after progeny have segregated. We now overexpression causes premature removal RNA primers joining on theta structures. Further elongation blocked, but leading completed progeny, truncated H (ranging from 0.1 kb), electrophorese an agarose gel smear. This replication defect associated shrinkage eventual slowing cell growth. propose unwinds synthesis, thus facilitating processing fragments.