Fig. 3. Transcripts for the GLG isoform are products of a single gene. (a) A 10 kb cloned genomic DNA fragment was digested either with EcoRI (E) or EcoRI plus BamHI (E/B), and analyzed with GLG isoform-specific probes. Those primers were amplified from the cDNA sequence for GLG1 and GLG2 using either primers 5 and 6 (for GLG1) or primers 3 and 4 (for GLG2), as shown in Fig. 1. DNA molecular weight markers for 4, 3, 2 and 1 kb were also shown. (b) Nucleotide sequences of 5' and 3' alternative splicing sites for GLG2 in the GLG genomic clones. The consensus sequences for spicing are indicated by asterisks. The translation stop codon for GLG1 is underlined. (c) A model for the production of GLG1 and GLG2 by alternative splicing. Isoform-specific probes were represented by lines on the 3'-UTR of GLG1 and 24 amino acids and its 3'-UTR of GLG2 transcripts.