Nucleotide Sequence, Expression, and Chromosomal Mapping of Mrp and Mapping of Five Related Sequences

We isolated and characterized a genomic clone for the mouse MARCKS-related protein, or MRP, also known as F52 and MacMARCKS. A 3699-bp plasmid contained 407 bp of 5′-flanking region, 186 bp of 5-untranslated region, 600 bp of protein coding region, 784 bp of a single intron, 746 bp of 3′-untranslated region, and 976 bp of 3′-flanking region. The position of the single intron was identical to the intron position in all known MARCKS mRNAs. When the plasmid containing the genomic sequences was transfected into fibroblasts lacking endogenous Mrp expression, the 407 bp of promoter conferred high-level expression of the full-length, spliced mRNA. The putative promoter was therefore functional; however, despite tissue-specific regulation and transcriptional induction in some cells in a manner similar to that seen with MARCKS expression, the promoters were highly dissimilar at the level of primary sequence (37% identity over 407 bp). Mrp mapped to a position on mouse chromosome 4 that was closely linked to the Lck locus. Numerous additional species that hybridized to the MRP cDNA were noted on Southern blotting of mouse genomic DNA. Five related loci were labeled Mrp-rs1 through Mrp-rs5 (for Mrp-related sequences) and were mapped to mouse chromosomes 10, 17, 15, 13, and X, respectively. Three of these related sequences have been cloned, and all appear to represent pseudogenes.