Structure of the human sarco/endoplasmic reticulum Ca2+-ATPase 3 gene. Promoter analysis and alternative splicing of the SERCA3 pre-mRNA.
Human chromosome 17-specific genomic clones extending over 90 kilobases (kb) of DNA and coding for sarco/endoplasmic reticulum Ca2+-ATPase 3 (SERCA3) were isolated. The presence of the D17S1828 genetic marker in the cosmid contig enabled us to map the SERCA3 gene (ATP2A3) 11 centimorgans from the top of the short arm p of chromosome 17, in the vicinity of the cystinosis gene locus. The SERCA3 gene contains 22 exons spread over 50 kb of genomic DNA. The exon/intron boundaries are well conserved between human SERCA3 and SERCA1 genes, except for the junction between exons 8 and 9 which is found in the SERCA1 gene but not in SERCA3 and SERCA2 genes. The transcription start site (+1) is located 152 nucleotides (nt) upstream of the AUG codon. The 5'-flanking region, including exon 1, is embedded in a 1.5-kb CpG island and is characterized by the absence of a TATA box and by the presence of 14 putative Sp1 sites, 11 CACCC boxes, 5 AP-2-binding motifs, 3 GGCTGGGG motifs, 3 CANNTG boxes, a GATA motif, as well as single sites for Ets-1, c-Myc, and TFIIIc. Functional promoter analysis indicated that the GC-rich region (87% G + C) from -135 to -31 is of critical importance in initiating SERCA3 gene transcription in Jurkat cells. Exon 21 (human, 101 base pairs; mouse, 86 base pairs) can be alternatively excluded, partially included, or totally included, thus generating, respectively, SERCA3a (human and mouse, 999 amino acids (aa)), SERCA3b (human, 1043 aa; mouse, 1038 aa), or SERCA3c (human, 1024 aa; mouse, 1021 aa) isoforms with different C termini. Expression of the mouse SERCA3 isoforms in COS-1 cells demonstrated their ability to function as active pumps, although with different apparent affinities for Ca2+.
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Laboratorium voor Fysiologie, Katholieke Universiteit Leuven, Campus Gasthuisberg, Herestraat 49, B-3000, Leuven, Belgium. Leo.Dode@med.kuleuven.ac.be
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D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D000252:Calcium-Transporting ATPases / Q000235:genetics*; D002886:Chromosomes, Human, Pair 17; D003001:Cloning, Molecular; D004247:DNA; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D005091:Exons; D006801:Humans; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012322:RNA Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
D012322:RNA Precursors; D012333:RNA, Messenger; D004247:DNA; D000252:Calcium-Transporting ATPases