SPATIAL LOCALIZATION OF TRANSCRIPTS OF THE HOX-C6 GENE

The Hox-C6 gene, in common with its Xenopus and human homologues, is o rganised as 3 exons with 2 distinct promoters (PRI and PRII) producing 2 different transcripts. The PRII promoter produces a 'typical' Hox t ranscript by splicing 2 exons separated by a 700 bp intron. The PRI pr omoter initiates transcription from a 3rd exon, 9 kbp 5' of PRII. This exon is spliced into the Ist exon of the PRII transcript at a point 3 ' of the translation start codon. This means that the predicted protei n product of the PRI protein contains the Hox-C6 homeodomain but is tr uncated by 82 amino acids compared with the PRII product. In situ hybr idisation using probes specific for PRI or PRII showed them to have es sentially the same distribution in the developing nervous system and p revertebrae of 12.5 d embryos. However, the distribution of transcript s in the CNS was distinctly different from that reported previously fo r a probe containing the Hox-C6 homeobox.