of Tn7: TnsA and TnsB interact together to form the transposase, while TnsC functions as a regulator of the transposase's activity, communicating between the transposase and TnsD and TnsE. When the TnsE protein interacts with the TnsABC core machinery, Tn7 preferentially directs insertions into conjugable plasmids. When the TnsD protein interacts with TnsABC, Tn7 preferentially directs insertions downstream into a single essential and highly conserved site in the bacterial chromosome. This site, attTn7, is specifically recognized by TnsD. References External links EC 2.7.7 Molecular biology Mobile genetic elements