Identification of a functional transposase of the Tol2 element, an Ac-like element from the Japanese medaka fish, and its transposition in the zebrafish germ lineage

Kawakami, K., Shima, A., and Kawakami, N.
Proceedings of the National Academy of Sciences of the United States of America   97(21): 11403-11408 (Journal)
Registered Authors
Kawakami, Koichi, Shima, Akihiro
MeSH Terms
  • Animals
  • Base Sequence
  • DNA
  • DNA Primers
  • DNA Transposable Elements*
  • Founder Effect
  • Germ Cells/enzymology*
  • Germ Cells/metabolism
  • Molecular Sequence Data
  • Oryzias/genetics*
  • Polymerase Chain Reaction
  • Sequence Homology, Nucleic Acid
  • Transposases/genetics*
11027340 Full text @ Proc. Natl. Acad. Sci. USA
The Tol2 element of the medaka fish Oryzias latipes belongs to the hAT family of transposons (hobo/Ac/Tam3). We report here identification of a functional transposase of Tol2 that is capable of catalyzing its transposition in the germ line of zebrafish Danio rerio. A transcript produced from Tol2 encodes a putative transposase. Zebrafish fertilized eggs were coinjected with mRNA transcribed in vitro, using cDNA of the Tol2 transcript as a template and a plasmid DNA harboring a mutant Tol2, which had a deletion in the putative transposase gene but retained necessary cis sequences. The injected fish were raised to adulthood and mated to noninjected fish, and genomic DNA of the progeny fish were analyzed by PCR and Southern hybridization. Half of F(1) fish obtained from one of eight injected fish contained the Tol2 DNA in their genomes but not the vector portion. Among these F(1) fish, Tol2 insertions at four different loci were identified, and some F(1) fish carried two or three different Tol2 insertions, indicating that the germ line of the founder fish is highly mosaic. Sequencing analyses revealed that, in all cases, Tol2 was surrounded by zebrafish genomic sequences, and an 8-bp duplication was created at the target site, indicating that Tol2 was integrated in the zebrafish genome through transposition. This study identifies an autonomous member of a DNA-based transposable element from a vertebrate genome. The Tol2 transposon system should thus be used to develop novel transgenesis and insertional mutagenesis methods in zebrafish and possibly in other fishes.
Genes / Markers
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes