Anti-MC1R monoclonal antibody, clone FQS7641

Bandicoot rats (genusBandicota), widely known as rodent pests, are abundant and widespread throughout the continental part of the Indo-Malayan realm. However, their evolutionary history is not yet well understood. The molecular phylogenetic relationships of the three bandicoot rat species,Bandicota bengalensis,Bandicota indica, andBandicota savilei, were assessed based on the gene sequences of the specimens collected from Myanmar, where all three species occur along with database sequences. Early divergence ofB. savilei(1.5-1.7 million years ago) was inferred from the mitochondrial cytochromeb(Cytb) gene and the nuclear interphotoreceptor retinoid-binding protein (Irbp), and melanocortin 1 receptor (Mc1r) gene sequences. TheCytblineage ofB. bengalensisfrom Sri Lanka was distinct from the monophyletic lineage of the continental lineages ofB. bengalensisandB. indica. This can be explained by the preservation of ancient mitochondrial DNA (mtDNA) in the insular population owing to female philopatry and male dispersal, given that no substantial intraspecies geographic subdivision was observed in the nuclear markers. The paraphyletic relationship ofB. bengalensiswithB. indicamay be explained by introgression of the mtDNA fromB. bengalensistoB. indica, but further investigation is required to confirm this.B. bengalensis Cytbsequences from a wide area of Myanmar had limited nucleotide diversity (pi = 0.00079), implying that the genetic diversity ofB. bengalensisin Myanmar was acquired through Holocene human activities.

Melanocortin-1 receptor (MC1R) has important roles in regulating pigmentation and inflammation. Melanocortin receptor accessory protein 2 (MRAP2) modulates trafficking, ligand binding, and signaling of mammalian melanocortin receptors. However, the effect of MRAP2 on fish MC1R has not been extensively studied. Herein, we cloned the orange-spotted grouper (Epinephelus coioides) mc1r, which had a 972 bp open reading frame encoding a putative protein of 323 amino acids. Grouper mclr was mainly expressed in the brain, skin, testis, spleen, head kidney, and kidney. EcoMC1R showed high constitutive activities in both Gs-cAMP and ERK1/2 pathways, which could be differentially modulated by grouper MRAP2 (EcoMRAP2). Three agonists, including alpha-melanocyte-stimulating hormone (MSH), beta-MSH, and ACTH, could bind to EcoMC1R and dose-dependently increase intracellular cAMP production. EcoMRAP2 had no effect on the IC50 in binding assay or EC50 in cAMP assay; however, it dose-dependently decreased the cell surface expression and maximal response to the three agonists. EcoMRAP2 increased basal ERK1/2 activation but did not alter alpha-MSH-stimulated ERK1/2 activation. This study extends the knowledge base of fish MC1R pharmacology and its regulation by MRAP2.