Transposons are interesting, abundant genomic elements that can have a significant impact on the genomes of their hosts. Because transposon movement throughout genomes can alter expression of surrounding genes and create regions of genome instability, regulation of transposition is important. This thesis focuses on understanding the mechanism and regulation of a bacterial DNA transposon, Tn7. Tn7 integrates site-specifically into a particular site called attTn7 using four transposon-encoded proteins, TnsA, TnsB, TnsC, and TnsD. Tn7 requires interaction between transposon ends and target DNA to initiate transposition. TnsC mediates this communication, thereby regulating Tn7. Experiments that identify the functional domains of TnsC will provide deeper insights into how Tn7 and other nucleoprotein complexes are controlled. In order to interrupt the tnsC gene and identify the functional domains, we generated TnsC mutants containing fifteen base pair insertions that can result in either five amino acid insertions or introduction of a stop codon using transposon-mediated insertional mutagenesis. The mutants were then tested for transposition activity. Notably, the data suggests that the C-terminus of TnsC that interacts with TnsA is capable of promoting transposition in the absence of the rest of the protein in vivo. Since only the TnsA-interacting domain is required for transposase activation, it is likely that the other functional domains regulate target DNA binding and recruitment into the transpososome. Characterization of the TnsB-TnsC interaction would provide a better understanding of TnsC's involvement in transpososome formation. A second strategy was used to determine how TnsC interacts with TnsB. To directly probe the TnsB-TnsC interaction, we developed a crosslinking system that provided the first evidence for a direct, physical protein-protein interaction between TnsB and TnsC. In this system we exploited a previously identified peptide of TnsB involved in the TnsB-TnsC interaction. Further analysis implicated a region in the C-terminus of TnsC in the interaction with TnsB. Because we have found that deletion of much of the N-terminus of TnsC allows activity not seen with intact protein, it is likely that the N-terminus regulates exposure of the transposition-stimulating C-terminus.