Comparative analysis of Xenopus VegT, the meso-endodermal determinant, identifies an unusual conserved sequence.
The transcription factor, VegT, is the meso-endodermal determinant in Xenopus laevis. We examined VegT orthologs from several anuran amphibians and the urodele amphibian, the Mexican axolotl. In addition to the conserved T-box, the DNA-binding domain, the orthologs share a conserved 57 amino acid domain at the C-terminal. Most striking is a 17-nucleotide (nt) sequence near the 3' end of the open reading frame. The 17 nts are absolutely conserved among the anurans, whose last common ancestor lived 200 million years ago. As an initial test of the function of the 17 nts, 27 or 49 amino acids, which include the six amino acids coded by the 17 (+1) nts, were deleted from the C-terminal of VegT. These truncated VegT's retained some transcriptional activity, indicating that the 17 nts are not absolutely required for this function. The function of the highly conserved 17 nts is unknown. Two possibilities are that the conserved 17 nts interact with the cytoskeleton or that they are a target for regulation by a microRNA.
Pérez
Oscar
O
Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.
Benítez
María-Soledad
MS
Nath
Kimberly
K
Heasman
Janet
J
Del Pino
Eugenia M
EM
Elinson
Richard P
RP
D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000145:classification / Q000378:metabolism*; D000818:Animals; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000502:physiology*; D004707:Endoderm / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000378:metabolism*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D020825:T-Box Domain Proteins / Q000235:genetics / Q000502:physiology*; D014981:Xenopus / Q000254:growth & development; D029867:Xenopus Proteins / Q000235:genetics / Q000502:physiology*
D029845:Amphibian Proteins; D020825:T-Box Domain Proteins; C103966:VegT protein, Xenopus; D029867:Xenopus Proteins