Aline Cristine Pereira E Silva1, Maria José Dos Santos1, Bruna Del Vechio Koike1, Magna Suzana Alexandre Moreira2, Daniel Leite Goes Gitai3, Jorge Artur Peçanha de Miranda Coelho4, Tiago Gomes de Andrade5. 1. Laboratory of Molecular Chronobiology, Federal University of Alagoas (UFAL), Alagoas, Brazil. 2. Laboratory of Pharmacology and Immunity, Federal University of Alagoas (UFAL), Alagoas, Brazil. 3. Laboratory of Cellular and Molecular Biology, Federal University of Alagoas (UFAL), Alagoas, Brazil. 4. Faculty of Medicine, Federal University of Alagoas (UFAL), Alagoas, Brazil. 5. Laboratory of Molecular Chronobiology, Federal University of Alagoas (UFAL), Alagoas, Brazil; Faculty of Medicine, Federal University of Alagoas (UFAL), Alagoas, Brazil. Electronic address: deandrade.tiago@pq.cnpq.br.
Abstract
BACKGROUND: Melatonin modulates the master circadian clock through the activation of G-protein-coupled receptors MT1 and MT2. It is presumed, therefore, that genetic variations in melatonin receptors can affect both sleep and circadian phase. We investigated whether the -1193T > C (rs4753426) polymorphism in the promoter of MT2 receptor gene (MTNR1B) is associated with diurnal preference and sleep habits. This polymorphism was previously associated with sunshine duration, suggesting a role in circadian entrainment. METHODS: A total of 814 subjects who completed the Morningness-Eveningness and the Munich Chronotype questionnaires were genotyped for the selected polymorphism. Linear and multinomial regression were performed to test the interaction between gene variants and diurnal preference/sleep habits. RESULTS: The -1193C variant was associated with the extreme morningness phenotype in a codominant model (C/C vs. T/T), recessive model (C/C + C/T vs. T/T) and alleles (C vs. T). A negative correlation was found between -1193C alleles and social jetlag scores. The frequency of -1193T allele was higher in the group that stay in bed more than 8 h/night compared to the group that stay in bed less than 8 h/night on weekends. CONCLUSION: To the best of our knowledge, these data provide the first insights into the role of MTNR1B gene in the regulation of sleep, biological rhythms, and entrainment in humans.
BACKGROUND:Melatonin modulates the master circadian clock through the activation of G-protein-coupled receptors MT1 and MT2. It is presumed, therefore, that genetic variations in melatonin receptors can affect both sleep and circadian phase. We investigated whether the -1193T > C (rs4753426) polymorphism in the promoter of MT2 receptor gene (MTNR1B) is associated with diurnal preference and sleep habits. This polymorphism was previously associated with sunshine duration, suggesting a role in circadian entrainment. METHODS: A total of 814 subjects who completed the Morningness-Eveningness and the Munich Chronotype questionnaires were genotyped for the selected polymorphism. Linear and multinomial regression were performed to test the interaction between gene variants and diurnal preference/sleep habits. RESULTS: The -1193C variant was associated with the extreme morningness phenotype in a codominant model (C/C vs. T/T), recessive model (C/C + C/T vs. T/T) and alleles (C vs. T). A negative correlation was found between -1193C alleles and social jetlag scores. The frequency of -1193T allele was higher in the group that stay in bed more than 8 h/night compared to the group that stay in bed less than 8 h/night on weekends. CONCLUSION: To the best of our knowledge, these data provide the first insights into the role of MTNR1B gene in the regulation of sleep, biological rhythms, and entrainment in humans.