Human Sp8 cDNA sequences encompassing the ORF and translation. (A) Sequence encoding exon 1a encoding the start of Sp8L protein isoform. (B) Sequence encoding the untranslated exon 1b encoding the Sp8S protein isoform. (C) Sequence encoding the common exon 2. The atg/methionine start codon for the long protein isoform is shown in bold and coloured red and that of the short protein isoform coloured pink. The ORF stop codon, tga, is shown in bold and coloured red and is indicated by a red asterisk. An in-frame stop codon, tag, in the 5'UTR of exon 1b is shown in bold and coloured red. The exon/exon boundaries were determined by comparison with the sequence of genomic DNA clone CTA-324D18. The nucleotides underlined and shown in bold type indicate the location of the exon/exon boundaries. The loss of a GGC (glycine) codon found in an additional Sp8 clone is shown in green and bolded.