Two alternative ACHEmRNA forms in human DAMI cells. Putative transcripts and PCR primer positions are schematically shown for the human ACHE gene. Exons (E) are represented by boxes. I, intron. AUG, site of initiator methionine. Inset: RT-PCR amplification of DAMI cells RNA followed by DNA blot hybridization using exons E2-E6 DNA as a probe. Two of three possible alternative forms of ACHEmRNA were detected. Length of expected PCR fragments is marked by arrowed line and deleted intron by dotted lines. Note that the E5-specific primers yielded a 399-bp, but not a 479-bp fragment, indicating complete exclusion of the I4 intron from DAMI ACHEmRNA.