The mechanism of transposition of Tc3 in C. elegans

A study of Tc3 transposase expression from heat-shock promoters in transgenic nematodes helps understand the Tc3 transposition pathway. The linear extrachromosomal Tc3 DNA that appears during transposition is cut incompletely, with two nucleotides being absent from the 5' ends. The nucleotides at the donor site lead to a distinct footprint. A model that depicts the excision and integration of the Tc3 element and target replication and traces the roots of the somatic footprints is suggested, based on the structure of the extrachromosomal DNA element.