期刊
MOLECULAR IMMUNOLOGY
卷 47, 期 9, 页码 1817-1829出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.molimm.2009.12.012
关键词
Major histocompatibility complex; Gene expression regulation; Repetitive sequences; Selection; Evolution; Salmonids
资金
- Valorisation Recherche Quebec (VRQ) through the auspices of the Reseau Aquaculture Quebec (RAQ)
- AquaNet
- Centres of Excellence Programs and Councils
- Universite de Montreal
It is widely recognized that the variation in gene regulation is an important factor from which evolutionary changes in diverse aspects of phenotype can be observed in all organisms. Distinctive elements with functional roles on gene regulation have been identified within the non-coding part of the genome, including repeated elements. Major histocompatibility complex (MHC) genes have been the subject of an abundant literature which made them unique candidates for studies of adaptation in natural populations. Yet, the vast majority of studies on MHC genes have dealt with patterns of polymorphism in sequence variation while very few paid attention to the possible implication of differential expression in adaptive responses. In this paper, we report the identification of a polymorphic minisatellite formed of a 32 nucleotides motif (38% G + C) involved in regulation of the major histocompatibility class up gene (MHII beta) of brook charr (Salvelinus fontinalis). Our main objectives were: to analyze the variability of this minisatellite found in the second intron of the MHII beta gene and to document its effect to the variation of expression level of this gene under different environmental conditions. Distinctive number of the minisatellite repeats were associated with each different MHII beta alleles identified from exon 2 sequences. Relative expression levels of specific alleles in heterozygous individuals were determined from fish lymphocytes in different genotypes. We found that alleles carrying the longest minisatellite showed a significant 1.67-2.56-fold reduction in the transcript expression relatively to the shortest one. Results obtained in three different genotypes also indicated that the repressive activity associated to the longest minisatellite was more effective at 18 degrees C compared to 6 degrees C. In contrast, no significant difference was observed in transcript levels between alleles with comparable minisatellite length at both temperatures. We also depicted a significant up-regulation of the total MHII beta transcript at 6 degrees C relative to 18 degrees C. These results reveal for the first time that a temperature-sensitive minisatellite could potentially play an important role in the gene regulation of the adaptive immune response in fishes. (c) 2010 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据