Characterization of the 3' end of the pig sarcoplasmic/endoplasmic-reticulum Ca2+ pump gene 2.

The gene 2 for the sarcoplasmic/endoplasmic-reticulum Ca2+ pump (SERCA2) is expressed both in muscle and non-muscle tissues and four distinct SERCA2 mRNAs which differ only in their 3' end have been described. In order to understand the differential 3' end processing of the SERCA2 transcripts, we have now cloned a 12.6 kb pig genomic clone which contains the 3' end of the pig SERCA2 gene. Part of this clone (7510 nucleotides) was sequenced and it was found to contain four constitutive exons followed by four optional exons which underlie the 3' end diversity of the SERCA2 mRNAs. The inclusion or the exclusion of these optional exons is explained by the presence of four optional processing sites: two polyadenylation sites and two optional donor splice sites.