ZFIN ID: ZDB-PUB-990106-15
Short inverted-repeat transposable elements in teleost fish and implications for a mechanism of their amplification
Izsvák, Z., Ivics, Z., Shimoda, N., Mohn, D., Okamoto, H., and Hackett, P.B.
Date: 1999
Source: Journal of molecular evolution 48: 13-21 (Journal)
Registered Authors: Hackett, Perry B., Ivics, Zoltan, Izsvák, Zsuzsa, Mohn, Deanna, Okamoto, Hitoshi, Shimoda, Nobuyoshi
Keywords: zebrafish; miniature inverted-repeat transposable; element (MITE); polymorphism;g genetic mapping; stem-loop; A/T-rich sequence; DNA replication and amplification; template switching
MeSH Terms: Animals; Base Sequence; Carps/genetics; DNA Transposable Elements/genetics*; Evolution, Molecular (all 18) expand
PubMed: 9873073 Full text @ J. Mol. Evol.
Angel is the first miniature inverted-repeat transposable element (MITE) isolated from fish. Angel elements are imperfect palindromes with the potential to form stem-loop structures in vitro. Despite sequence divergence of elements of up to 55% within and between species, their inverted repeat structures have been maintained, implying functional importance. We estimate that there are about 10(3)-10(4) Angels scattered throughout the zebrafish genome, evidence that this family of transposable elements has been significantly amplified over the course of evolution. Angel elements and Xenopus MITEs carry common sequence motifs at their termini, indicating common origin and/or related mechanisms of transposition. We present a model in which MITEs take advantage of the basic cellular mechanism of DNA replication for their amplification, which is dependent on the characteristic inverted repeat structures of these elements. We propose that MITEs are genomic parasites that transpose via a DNA intermediate, which forms by a folding-back of a single strand of DNA, that borrow all of the necessary factors for their amplification from products encoded in the genomes in which they reside. DNA polymorphisms in different lines of zebrafish were detected by PCR using Angel-specific primers, indicating that such elements, combined with other transposons in vertebrate genomes, will be useful molecular tools for genome mapping and genetic analyses of mutations.