Fig. 2.

The brain-specific splice variant Vti1a-β had an insertion of seven amino acid residues. A, A single band was PCR-amplified from a lung cDNA library, a double band from a cerebellum cDNA library using primers specific for Vti1a. The slightly larger band encoded Vti1a-β with a insertion of seven amino acids after Q114. B, Expression pattern of Vti1a and Vti1a-β in different tissues. RT-PCRs were performed using primer pairs amplifying both Vti1a and Vti1a-β (expected sizes, 511 and 490 bp;top), Vti1a only (forward primer annealing with codons 110–116, 265 bp; middle), or Vti1a-β only (forward primer annealing with Vti1a-β-specific codons 115–121, 253 bp;bottom). Vti1a was amplified from all tissues examined. Vti1a-β was amplified from the neuronal tissues cerebellum, cortex, and hippocampus, but not from lung, liver, kidney, or spleen.C, Alignment of Saccharomyces cerevisiaeVti1p, the C-terminal part of a predicted C. elegansprotein (GenBank accession number CAB16506), mouse Vti1b, rat Vti1a (GenBank accession number AF262221), and rat Vti1a-β (GenBank accession number AF262222). Filled circles indicate the beginning and end of the predicted SNARE-interacting helix (SNARE motif). The open circle marks the position of the conserved glutamine or aspartate residue in layer 0, andasterisks indicate hydrophobic positions in the heptade repeats.