Gambol and Tc1 are two distinct families of DD34E transposons: analysis of the Anopheles gambiae genome expands the diversity of the IS630-Tc1-mariner superfamily

• Published in: Insect molecular biology Vol. 14; no. 5; pp. 537 - 546
• Main Authors: Coy, M.R, Tu, Z
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.10.2005; Blackwell Publishing Ltd
• Subjects: Amino Acid Sequence; Animals; Anopheles - genetics; Anopheles gambiae; Chromosome Mapping; consensus sequence; DNA binding; DNA Transposable Elements - genetics; DNA-binding domains; DNA-Binding Proteins - genetics; evolution; Genetic Variation; genome; genomics; insect genetics; Insect Proteins - genetics; interspersed repeat; Molecular Sequence Data; mosquito; Multigene Family - genetics; Phylogeny; Protein Binding; Protein Structure, Tertiary; repetitive sequences; sequence analysis; sequence homology; transposable element; transposase sequences; transposons
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/j.1365-2583.2005.00584.x

Tc1 is a family of DNA transposons found in diverse organisms including vertebrates, invertebrates and fungi. Tc1 belongs to the IS630-Tc1-mariner superfamily, which is characterized by common 'TA' target site and conserved D(Asp)DE(Glu) or DDD catalytic triad. All functional Tc1-like transposons contain a transposase with a DD34E catalytic triad. We conducted a systematic analysis of DD34E transposons in the African malaria mosquito, Anopheles gambiae, using a reiterative and exhaustive search program. In addition to previously described Tc1-like elements, we uncovered 26 new DD34E transposons including a novel family that we named gambol. Designation of family status to gambol is based on phylogenetic analyses of transposase sequences that showed gambol and Tc1 transposons as distinct clades that were separated by mariner and other families of the IS630-Tc1-mariner superfamily. The distinction between Tc1 and gambol is also consistent with the unique TIRs in gambol elements and the presence of a 'WI/L/VDEDC' signature near their N-termini. This signature is predicted as part of the 'RED' domain, a component of the 'PAI' and 'RED' DNA binding domains in Tc1 and possibly mariner. Although gambol appears to be related to a few DD34E transposons from cyanobacteria and fungl, no gambol has been reported in any other insects or animals thus far. Several gambol and Tc1 elements have intact ORFs and different genomic copies with high sequence identity, which suggests that they may have been recently active.