Fig. 4. Reassignment of the 5 end of the human ryanodine receptor subtype 1 transcript. (A ) Portion of the sequencing trace showing the junction of the transcript end and the polyA tail attached during the rapid amplification of complementary ends (RACE) procedure. Between the polyA tail and the specific sequence are three noncomplementary cytidine residues that are appended during reverse transcription (see text). (B ) Alignment of genomic and transcript sequences of ryanodine receptor subtype 1 (RYR1 ) genes of several mammals. All sequences, except mouse EST BB608312 (designated Mm_expressed sequence tag) and the sequence obtained in this work (Hs_RACE), are designated by their Genbank accession numbers.