Fig. 1.

Sequences of BCCa-I and BCCa-II, the calcium channel fragments amplified from bag cell neuron RNA. PCR primers A1 and A2 were used to amplify partial sequences of calcium channel α₁ subunits from reverse-transcribed RNA isolated from bag cell clusters, as described in Materials and Methods.A, Transmembrane structure of an α₁subunit indicating the four domains and the positions of the two PCR primers A1 and A2 (triangles). The conserved protein sequences targeted by each primer are indicated inparentheses, with capital lettersindicating complete conservation in vertebrate α₁-subunit sequences. The amplified region is shaded black.B, The consensus nucleotide sequences of the amplified fragments and their corresponding protein sequences BCCa-I and BCCa-II. The regions used in the fusion protein constructs FP-I and FP-II are shown in boldface. Transmembrane regions areshaded. Potential sites of PKC phosphorylation arecircled. Asterisks indicate two sites of ambiguity in the BCCa-II nucleotide sequence (see Materials and Methods). Alignment was performed using the GAP program of the Wisconsin Package (see Materials and Methods).