hAT transposons are a superfamily of DNA transposons, or Class II transposable elements, that are common in the genomes of plants, animals, and fungi.[1][2][3]
Nomenclature and classification[edit]
Superfamilies are identified by shared DNA sequence and ability to respond to the same transposase.[1] Common features of hAT transposons include a size of 2.5-5 kilobases with short terminal inverted repeats and short flanking target site duplications generated during the transposition process.[3]
The hAT superfamily's name derives from three of its members: the hobo element from Drosophila melanogaster, the Activator or Ac element from Zea mays, and the Tam3 element from Antirrhinum majus.[4] The superfamily has been divided based on bioinformatics analysis into at least two clusters defined by their phylogenetic relationships: the Ac family and the Buster family.[1] More recently, a third group called Tip has been described.[3]
Family members[edit]
The hAT transposon superfamily includes the first transposon discovered, Ac from Zea mays (maize), first reported by Barbara McClintock.[1][5] McClintock was awarded the Nobel Prize in Physiology or Medicine in 1983 for this discovery.[6] The family also includes a subgroup known as space invaders or SPIN elements, which have very high copy numbers in some genomes and which are among the most efficient known transposons. Although no extant active example is known, laboratory-generated consensus sequences of active SPIN elements are able to generate high copy numbers when introduced to cells from a wide range of species.[1][7]
Distribution[edit]
hAT transposons are widely distributed across eukaryotic genomes, but are not active in all organisms. Inactive hAT transposon sequences are present in mammal genomes, including the human genome;[1] they are among the transposon families believed to have been present in the ancestral vertebrate genome.[8] Among mammals, the genome of the little brown bat Myotis lucifugus is notable for its relatively high and recently acquired number of inactive hAT transposons.[1]
The distribution of SPIN elements is patchy and does not relate well to known phylogenetic relationships, prompting suggestions that these elements may have spread through horizontal gene transfer.[1][7]
Domestication[edit]
Transposons are said to be exapted or "domesticated" when they have acquired functional roles in the host genome. Several sequences evolutionarily related to the hAT family have been exapted in diverse organisms, including Homo sapiens.[1] An example is the ZBED gene family, which encode a group of zinc finger-containing regulatory proteins.[9]
References[edit]
- ^ a b c d e f g h i Arensburger, Peter; Hice, Robert H.; Zhou, Liqin; Smith, Ryan C.; Tom, Ariane C.; Wright, Jennifer A.; Knapp, Joshua; O'Brochta, David A.; Craig, Nancy L.; Atkinson, Peter W. (May 2011). "Phylogenetic and Functional Characterization of the Transposon Superfamily". Genetics. 188 (1): 45–57. doi:10.1534/genetics.111.126813. PMC 3120152. PMID 21368277.
- ^ Kempken, F; Windhofer, F (April 2001). "The hAT family: a versatile transposon group common to plants, fungi, animals, and man". Chromosoma. 110 (1): 1–9. doi:10.1007/s004120000118. PMID 11398971. S2CID 1925295.
- ^ a b c Rossato, Dirleane Ottonelli; Ludwig, Adriana; Deprá, Maríndia; Loreto, Elgion L. S.; Ruiz, Alfredo; Valente, Vera L. S. (February 2014). "BuT2 Is a Member of the Third Major Group of hAT Transposons and Is Involved in Horizontal Transfer Events in the Genus Drosophila". Genome Biology and Evolution. 6 (2): 352–365. doi:10.1093/gbe/evu017. PMC 3942097. PMID 24459285.
- ^ Rubin, E; Lithwick, G; Levy, AA (July 2001). "Structure and evolution of the hAT transposon superfamily". Genetics. 158 (3): 949–57. doi:10.1093/genetics/158.3.949. PMC 1461711. PMID 11454746.
- ^ McCLINTOCK, B (June 1950). "The origin and behavior of mutable loci in maize". Proceedings of the National Academy of Sciences of the United States of America. 36 (6): 344–55. Bibcode:1950PNAS...36..344M. doi:10.1073/pnas.36.6.344. PMC 1063197. PMID 15430309.
- ^ "The Nobel Prize in Physiology or Medicine 1983". Nobelprize.org. Retrieved 8 September 2018.
- ^ a b Li, X.; Ewis, H.; Hice, R. H.; Malani, N.; Parker, N.; Zhou, L.; Feschotte, C.; Bushman, F. D.; Atkinson, P. W.; Craig, N. L. (22 October 2012). "A resurrected mammalian hAT transposable element and a closely related insect element are highly active in human cell culture". Proceedings of the National Academy of Sciences. 110 (6): E478–E487. doi:10.1073/pnas.1121543109. PMC 3568352. PMID 23091042.
- ^ Chalopin, Domitille; Naville, Magali; Plard, Floriane; Galiana, Delphine; Volff, Jean-Nicolas (February 2015). "Comparative Analysis of Transposable Elements Highlights Mobilome Diversity and Evolution in Vertebrates". Genome Biology and Evolution. 7 (2): 567–580. doi:10.1093/gbe/evv005. PMC 4350176. PMID 25577199.
- ^ Hayward, Alexander; Ghazal, Awaisa; Andersson, Göran; Andersson, Leif; Jern, Patric; Robinson-Rechavi, Marc (22 March 2013). "ZBED Evolution: Repeated Utilization of DNA Transposons as Regulators of Diverse Host Functions". PLOS ONE. 8 (3): e59940. Bibcode:2013PLoSO...859940H. doi:10.1371/journal.pone.0059940. PMC 3606216. PMID 23533661.