Cloning and functional analysis of a polymorphic variant of the ovine Mel 1a melatonin receptor

Abstract

We have isolated a novel variant of the Mel 1a melatonin receptor from an ovine PT cDNA library. Relative to the reported sequence for the Mel 1a melatonin receptor there are 8 changes in the DNA sequence. Only 3 of these result in amino acid substitutions, one in extracellular loop 3 and two in the carboxy-terminal tail. We have designated the novel variant of the sheep Mel 1a receptor Mel 1a(beta), and correspondingly the previously reported variant Mel 1a(alpha). As minor changes in the primary amino acid sequence of G-protein-coupled receptors can influence their functional characteristics we have accordingly characterized this novel variant of the Mel 1a melatonin receptor. This melatonin receptor displays high affinity binding and inhibits the cAMP second messenger pathway in transfected L-cells demonstrating that this receptor is fully functional. PCR analysis shows Mel 1a(beta) is present in several breeds of sheep and suggests that the Mel 1a(beta) receptor was established early in the evolution of the sheep species.

Opportunities for detection and use of QTL influencing seasonal reproduction in sheep: a review

“…Relative to the sequence for ovine MTNR1A reported by Reppert et al [37], Barrett et al [3] found a variant form with eight base changes, three of which resulted in amino acid substitutions in the receptor. Subsequent breed comparisons indicated that both forms of the gene were present in samples of six Greyface × Suffolk ewes, six Greyface × Dorset ewes, and six Soay rams (Tab.…”

“…Molecular characterization of sequence variants in the ovine melatonin receptor la gene (MTNR1A) was reported by Barrett et al [3] and Messer et al [24]. Relative to the sequence for ovine MTNR1A reported by Reppert et al [37], Barrett et al [3] found a variant form with eight base changes, three of which resulted in amino acid substitutions in the receptor.…”

Distribution of Different Alleles of Aromatase Cytochrome P450 (CYP19) and Melatonin Receptor 1A (MTRN1A)Genes among Native Turkish Sheep Breeds

“…Melatonin is called the "hormone of darkness, " because it is released by the pineal gland during the night. The pattern of secretion of melatonin provides information that is apparently 'read' by cells within the brain that have the appropriate receptors and controls reproductive function [7,8] . In mammals, two high-affinity melatonin receptor subtypes have been cloned and characterized, namely the MTNR1A and MTNR1B receptors, also known as the MT1 and MT2 receptors, respectively [9,10] .…”

Sakız, Akkaraman ve İvesi Koyun Irklarında Melatonin Reseptör 1A (MTRN1A) Gen Polimorfizmi

“…The melatonin receptor 1A (MTNR1A) gene has been maped to ovine chromosome 26 and represents two RFLP polymorphic sites, one for MnlI enzyme and one for RsaI enzyme 9 . There are eight sites identified by the MnlI enzyme within the amplified sequence [9][10][11] . Some studies on meat sheep breeds point out that the presence of the cleavage sites for MnlI and RsaI enzyme in position 606 and 612 respectively and investigated the effects of these genotypes on the reproductive activity 7,10 .…”