Molecular characterization of CART, AgRP, and MC4R genes and their expression with fasting and re-feeding in common carp (Cyprinus carpio)

Abstract

Cocaine and amphetamine-regulated transcript (CART), agouti-related proteins (AgRP) and Melanocortin 4 Receptor (MC4R) involves in the control of appetite. The genes were cloned and characterized, and their regulation was studied in common carp. The CARTI and CARTII genes encode 117- and 120-amino acids, respectively. The AgRP-1 and AgRP-2 genes encode 128- and 136-amino acids, respectively. CARTI was principally expressed in the brain, eye and ovary, while CARTII was highly expressed in the brain. AgRP-1 was strongly expressed in the brain, intestine, testis and eye, while AgRP-2 was highly expressed only in the gill and eye. The MC4R gene, encoding 326-amino acids, was mainly expressed in the brain testis, pituitary and eye. Phylogenetic analysis had been conducted which implied that both CARTI/CARTII and AgRP-1/AgRP-2 might derived from gene duplication events during genome evolution of common carp. CART, AgRP and MC4R gene expression in brain were decreased after fasting treatment and increased sharply after refeeding comparing with normal fed controls, which suggested that CART, AgRP and MC4R are involved in appetite regulation in common carp.

Increased food intake in growth hormone-transgenic common carp (Cyprinus carpio L.) may be mediated by upregulating Agouti-related protein (AgRP)

“…Moreover, fasting led to upregulation of AgRP mRNA in the hypothalamus of goldfish and zebrafish (Danio rerio) Song et al, 2003). Two AgRP genes, AgRP I and AgRP II, have been identified in common carp (Wan et al, 2012). Orexins consist of two peptides, orexin A and orexin B encoded by a same precursor, prepro-orexin.…”

“…MC4R, a G protein-coupled receptor of a-MSH, possesses seven transmembrane-domain regions and mediates a-MSH to tonic restraint on feeding (CerdaReverter et al, 2003;Ringholm et al, 2002). In common carp, two forms of pre-pro-CART derived from separate genes have been identified (Wan et al, 2012). As a well-known appetite inhibiting factor (Volkoff andPeter, 2000, 2001), CART mRNA expression undergoes postprandial increases in common carp (Wan et al, 2012).…”

“…In common carp, two forms of pre-pro-CART derived from separate genes have been identified (Wan et al, 2012). As a well-known appetite inhibiting factor (Volkoff andPeter, 2000, 2001), CART mRNA expression undergoes postprandial increases in common carp (Wan et al, 2012). Cholecystokinin (CCK), a satiety signal mainly produced in the gut and brain, decreases food intake and feeding behavior (Himick and Peter, 1994;Volkoff, 2006).…”

Melanocortin-4 Receptor in Fish: A Review

“…Further research showed that common carp MC4R was highly expressed in brain, testis, and eye, followed by expression in the pituitary and heart [26]. Recent study on grass carp showed that MC4R was found to be highly expressed in the brain and eye, but expressed at low levels in the muscle, heart, intestine, liver, gill, spleen, and kidney [28].…”

“…Haitina et al [25] Cypriniforms Danio rerio Ringholm et al [19] Cyprinus carpio Wan et al [26] Carassius auratus Cerda-Reverter et al [27] Ctenopharyngodon idella Li et al [28] Luciobrama macrocephalus Tao et al [29] Schizothorax prenanti Wei et al [30] Xiphophorus maculatus Volff et al [31] Chondrichthyes Squaliformes Squalus acanthias Ringholm et al [32] Heterodontiformes H e terondotus francisci Baron et al [33] Myliobatiformes…”