The murine perilipin gene: the lipid droplet-associated perilipins derive from tissue-specific, mRNA splice variants and define a gene family of ancient origin

The Perilipins are a family of intracellular neutral lipid droplet storage proteins that are responsive to acute protein kinase A-mediated, hormonal s timulation. Perilipin (Peri) expression appears to be limited to adipocytes and steroidogenic cells, in which intracellular neutral lipid hydrolysis i s regulated by protein kinase A. We have isolated cDNA sets and overlapping genomic fragments of the murine Peri locus and mapped chromosomal location , transcription start sites, polyadenylylation sites, and intron/exon junct ions. Data confirm that the Perilipins are encoded by a single-copy gene, w ith alternative and tissue-specific, mRNA splicing and polyadenylylation yi elding four different protein species. The Perilipin proteins have identica l similar to 22-kDa amino termini with distinct carboxyl terminal sequences of varying lengths. These genomic and transcriptional maps of murine. Peri lipin are also essential for evaluating presumptive endogenous and targeted mutations within the locus. The N-terminal identity region of the Perilipi ns defines a sequence motif, which we term PAT, that is shared with the ADR P and TIP47 proteins; additionally, the PAT domain may represent a novel, c onserved pattern for lipid storage droplet (LSD) proteins of vertebrates an d invertebrates alike. Comparative genomics suggest the presence of related LSD genes in species as diverse as Drosophila and Dictyostelium.