Xenopus Adenine Nucleotide Translocase mRNA Exhibits Specific and Dynamic Patterns of Expression During Development

by: Michael J Crawford1*, Farhad KhosrowShahian*, Richard A Liversage+, Susannah L Varmuza+
*Dept. Biological Sciences, University of Windsor, Windsor, Ontario, N9B 3P4
+Dept. Zoology, University of Toronto, Toronto, Ontario, M5S 1A1
CANADA

ABSTRACT

 We report the isolation and characterization of the Xenopus homolog to human T1 ANT (adenine nucleotide translocase)  The 1290 nucleotide sequence contains initiation and termination signals, and encodes a conceptual protein of 298 amino acids.  The sequence shares high amino acid identity with the mammalian adenine translocases.  The transcript is present in unfertilized eggs, and it is expressed at higher levels during formation of the antero-posterior dorsal axis in embryos.  Although low levels are expressed constitutively except in endodermal cells, ANT expression is dynamically regulated during neurulation.  At this stage expression in ectoderm rapidly diminishes as the neural folds form, and then ANT expression increases slightly in mesoderm. At the culmination of neurulation, the neural tube briefly expresses ANT, and thereafter its expression predominates in the somitic mesoderm and also the chordoneural hinge. In addition, ANT expression is particularly high in the prosencephalon, the mesencephalon, the branchial arches, eye, and the otic vesicle.  Treatment of embryos with retinoic acid has the effect of diminishing constitutive expression of ANT, but microinjection studies demonstrate that immediate and local repression cannot be induced in dorsal structures.

Keywords:  adenine nucleotide translocase, Xenopus, retinoic acid, pattern formation, gastrulation.