STRUCTURE OF ARTEMIA-FRANCISCANA SARCO ENDOPLASMIC RETICULUM CA-ATPASE GENE/

Genomic clones coding for the Artemia franciscana sarco(endo)plasmic r eticulum Ca-ATPase have been isolated. The restriction map of the over lapping clones covers a region of 65 kilobases of DNA, Nucleotide sequ ence of mRNA coding regions shows that the gene is divided into 18 exo ns separated by 17 introns. Compared with the structure of the rabbit sarco(endo)plasmic reticulum Ca-ATPase 1 gene, 12 of the introns are i n the same position, 8 introns present in the rabbit gene are absent f rom A. franciscana, 4 introns present in A. franciscana are not found in rabbit, and the position of 1 intron is shifted one base between bo th genes. Southern blot analysis strongly suggests that this is the on ly sarco(endo)plasmic reticulum Ca-ATPase gene present in A. francisca na. Primer extension and nuclease S1 protection experiments have shown the existence of two main regions of transcription initiation separat ed by 30 nucleotides. Transcription is initiated in both regions at tw o or three consecutive bases. A hexanucleotide that includes the initi ation sites is repeated in both transcription initiation regions. The nucleotide sequence of the promoter region shows the existence of seve ral putative regulatory sites, including some that are muscle-specific such as one CArG box, 3 MEF-2, and 8 putative binding sites for muscl e transcription factors of the MyoD family.