Uniform TitleOrigination of Ds elements from Ac elements in maize: characterization of Ac derivatives from bz-m39(Ac)
NamePan, Hongbo (author), Dooner, Hugo (chair), Messing, Joachim (internal member), Maliga, Pal (internal member), Rutgers University, Graduate School - New Brunswick,
DescriptionThe maize genome contains a large number of both DNA transposons and retrotransposons. It is already known that retrotransposons are located in the highly methylated intergenic regions where recombination does not take place. However, DNA transposons are located in the eukaryotic regions of the maize genome, where they are able to interact with the host genes. It has been recently known that two transposable elements in direct orientation in the same chromosome may recombine occasionally with each other, which leads to the deletion of the intervening fragment. Based on this fact, it would be interesting to find out whether two elements in different homologues are able to recombine at meiosis. A series of Ac derivatives that originated de novo from bz-m39 (Ac) have been generated previously by Dr Dooner's lab. Some of these Ds derivatives appear to be large ([greater than] 4kb) based on Southern blots. It may be possible to recombine two Ds elements with non-overlapping deletions to reconstruct a 4565-bp Ac element. Hence these derivatives' exact sequence composition needs to be defined. In this research project, I characterized 23 Ac-derivatives, and the results indicate that most of these derivatives are composed of fragmented transposon structures. Some of them are Ds elements with or without filler DNA; some of them are single-ended fractured Ac (fAc) elements with either 5' or 3' missing ends, yet not transposed, which have not been reported before, indicating that Ac may undergo not only internal deletions but also terminal deletions that are sometimes accompanied by deletion of its flanking sequence. Microhomology, which is the main mechanism to explain the non-homologous end-joining repair of deletions in Ac, was discovered at the deletion junctions of most of these derivatives. The next step is to select suitable derivatives to carry out the recombination experiment by crossing and measuring the frequency of meiotic recombination within the transposable element (TE) in bz, which will be compared then to recombination in bz. Here, I present the molecular analysis of these 23 derivatives.
NoteIncludes bibliographical references (p. 44-46).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.