Nancy L. Craig
Johns Hopkins University
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Primary Section: 21, Biochemistry Secondary Section: 26, Genetics Membership Type:
Member
(elected 2010)
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Research Interests
I am interested in the mobile DNA elements called transposable elements that can move between non-homologous genome positions. My research has focused on those elements that move by excision from a donor site and insertion into a target site. We have studied elements from both bacteria and eukaryotes, the Tn7 element from Escherichia coli, hAT elements from insects and fish and a piggyBac element from insects. We have also discovered the first active mammalian excision & integration element, a piggyBac element from the little brown bat. My laboratory has used biochemical approaches to dissect transposition in all these systems by purifying the transposon-encoded transposase protein that mediates transposition, defining the required DNA substrates and analyzing their molecular interactions in the test tube. Despite the disparate origins of these transposon systems, their fundamental biochemical steps are the same and the core structures of the transposases are the same. We have also exploited genetically tractable systems to isolate transposition proteins with altered properties to probe transposition mechanism, using Tn7 in E. coli and showing that hAT and piggyBac elements can transpose in Saccharomyces cerevisiae. We have also used these systems to isolate hyperactive transposases to facilitate transposon-mediated genome engineering such as insertional mutagenesis and transgenesis.
