A Xenopus laevis gene encodes both homeobox-containing and homeobox-less transcripts

EMBO J. 1987 Dec 20;6(13):4083-94.


A cDNA clone (p52) that contains all the protein-coding region from the maternally expressed XlHbox 2 locus of the frog Xenopus laevis has been isolated and sequenced. A probe containing the exon preceding the homeobox detected transcripts which arise from a splicing event in which the homeobox-containing exon is replaced by another exon lying 5' to it in the genome. Both the homeobox-containing and homeobox-less splicing event occur in the same tissues, with the homeobox-less RNA representing the minority of mRNA from this gene. There may therefore be a function for two types of transcript, and hence protein, from this locus. This phenomenon may not be exclusive to the XlHbox 2 gene of Xenopus, but might occur more generally in other homeobox-containing genes. The protein deduced from the homeobox-containing cDNA is significantly similar to the yeast mating type factor a1 (MAT-a1) gene product. In addition to the previously described homology of the homeodomains, the amino-terminal domains of XlHbox 2 and MAT-a1 are similar to each other; thus essentially all of the MAT-a1 protein corresponds to some part of the XlHbox 2 protein. In the case of XlHbox 2, the protein coded for by the homeoboxless mRNA would contain all of the non-homeobox homology to yeast MAT-a1.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Codon
  • Embryo, Nonmammalian
  • Genes*
  • Genes, Homeobox*
  • Molecular Sequence Data
  • RNA, Messenger / genetics
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Nucleic Acid
  • Transcription, Genetic*
  • Xenopus laevis / genetics*


  • Codon
  • RNA, Messenger

Associated data

  • GENBANK/X06592
  • GENBANK/X06593