Alternatively spliced Hox-1.7 transcripts encode different protein products.

Two Hox-1.7 cDNAs, GPK5 and GPK6, were isolated from an adult guinea-pig kidney cDNA library by hybridization at low stringency using a Hox-1.7 cDNA probe, MH-1, cloned from mouse F9 teratocarcinoma cells. Sequence analysis of these two Hox-1.7 cDNAs showed that (a) GPK5 contains a putative initiation codon preceding an open reading frame which includes the homeo box, and may represent the complete protein coding region for the corresponding Hox-1.7 transcript; (b) the amino acids encoded by GPK6 and MH-1 are nearly identical (with two changes); (c) both adult guinea-pig kidney cDNA clones share identical homeo domains with the mouse Hox-1.7 cDNA; and (d) both adult guinea-pig kidney cDNA clones are identical in the homeo box region and in the 3' untranslated region but differ significantly starting from the 12th codon upstream from the homeo box. These data, supported by Southern blot analysis, indicate that a splice site is present 5' to the homeo box and that alternative splicing results in transcripts encoding different protein products.