We have learned an enormous amount in the past budget period about the mechanism and biology ofone of the major components of the human genome, the LI (LINE) retrotransposon. This remarkableelement is responsible, directly or indirectly, for about one third of our genome by weight; its reversetranscriptase ORF (ORF2) is the most abundant ORF in the human genome. Recent gains inunderstanding how this element works result from technical breakthroughs. We conceived of,developed and exploited a new synthetic retrotransposon that is approximately 200-fold more efficient than a nativeelement. We will use human tissue culture cell, in vitro and in silico systems to analyze the molecularmechanisms by which the LI element replicates and inserts itself into new sites. We will alsoinvestigate the mechanism and consequences of a newly discovered expression regulatory phenomenonwe discovered in LI, namely that its ORF sequences block transcriptional elongation. In the oppositeorientation they lead to premature polyadenylation. These combined effects may affect the expressionof many human genes and the responsible insertion polymorphisms may well underlie complex traitssuch as cancer susceptibility. These hypotheses will be tested. Finally, we are building a transgenicsynthetic retrotransposon mouse model that should provide technology for a) making genome wideknockout mutation collections and b) discovery of tumor suppressor genes in leukemia and othercancers.
Showing the most recent 10 out of 246 publications
