CHAPTER 43 – Models of Repair Underlying Trinucleotide DNA Expansion

摘要: This chapter focuses on repair-dependent models for the expansion at a DNA break. The first and most straightforward mechanism proposed opening was polymerase slippage during mitosis. In this model, dissociates from repeat segment template strand synthesis “slips” back to pair previously replicated triplet unit. forms an extrahelical loop that can be incorporated into DNA. Although unpairing reactions in duplex are energetically unfavorable, is possible because reaction occurs largely when falls off Because hydrogen-bonded structures appear important intermediates expansion, rapid stable intrastrand hydrogen bonding likely allow prevail over reannealing. However, mitotic replication model predicts should occur both daughter strands, relatively equal number of contraction events would expected.