Identification of alcohol preference relevant genes in QTL on mouse chromosome 2
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SUBMITTER: Wang L
PROVIDER: S-EPMC3194210 | biostudies-literature | 2011 Jan
REPOSITORIES: biostudies-literature
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Project description:Male fertility disorders often have their origin in disturbed spermatogenesis, which can be induced by genetic factors. In this study, we used interspecific recombinant congenic mouse strains (IRCS) to identify genes responsible for male infertility. Using ultrasonography, in vivo and in vitro fertilization (IVF) and electron microscopy, the phenotyping of several IRCS carrying mouse chromosome 1 segments of Mus spretus origin revealed a decrease in the ability of sperm to fertilize. This teratozoospermia included the abnormal anchoring of the acrosome to the nucleus and a persistence of residual bodies at the level of epididymal sperm midpiece. We identified a quantitative trait locus (QTL) responsible for these phenotypes and we have proposed a short list of candidate genes specifically expressed in spermatids. The future functional validation of candidate genes should allow the identification of new genes and mechanisms involved in male infertility.
| S-EPMC7697627 | biostudies-literature
Project description:A highly significant quantitative trait locus (QTL) that influenced alcohol preference was identified in the iP/iNP rats on chromosome 4. Congenic strains in which the iP chromosome 4 QTL interval was transferred to the iNP (NP.P) exhibited the expected increase in alcohol consumption compared to the iNP background strain. This study was undertaken to identify genes in the chromosome 4 QTL interval that might contribute to the differences in alcohol consumption between the alcohol-naïve congenic and background strains. RNA from five brain regions from each of 6 NP.P and 6 iNP rats was labeled and analyzed separately on an Affymetrix Rat Genome 230 2.0 microarray. Expression levels were normalized using robust multi-chip average (RMA). Differential gene expression was validated using quantitative real-time PCR. An analysis combining five brain regions, including nucleus accumbens, frontal cortex, amygdala, hippocampus, and striatum, identified twenty three transcripts and nine ESTs that were differentially expressed between the NP.P and iNP. Of the twenty three observed transcripts, thirteen were known genes, 9 were predicted genes and all but one were located in the chromosome 4 QTL interval. Very interesting cis-regulated candidate genes for alcohol consumption were identified using microarray profiling of gene expression differences in congenic animals carrying a QTL for alcohol preference. Keywords: alcohol, congenic, rat, gene expression, brain, nucleus accumbens, amygdala, frontal cortex, hippocampus, striatum
2008-02-01 | GSE5849 | GEO
Project description:BackgroundThe SMXA-5 mouse is an animal model of high-fat diet-induced fatty liver. The major QTL for fatty liver, Fl1sa on chromosome 12, was identified in a SM/J × SMXA-5 intercross. The SMXA-5 genome consists of the SM/J and A/J genomes, and the A/J allele of Fl1sa is a fatty liver-susceptibility allele. The existence of the responsible genes for fatty liver within Fl1sa was confirmed in A/J-12(SM) consomic mice. The aim of this study was to identify candidate genes for Fl1sa, and to investigate whether the identified genes affect the lipid metabolism.ResultsA/J-12(SM) mice showed a significantly lower liver triglyceride content compared to A/J mice when fed the high-fat diet for 7 weeks. We detected differences in the accumulation of liver lipids in response to the high-fat diet between A/J and A/J-12(SM) consomic mice. To identify candidate genes for Fl1sa, we performed DNA microarray analysis using the livers of A/J-12(SM) and A/J mice fed the high-fat diet. The mRNA levels of three genes (Iah1, Rrm2, Prkd1) in the chromosomal region of Fl1sa were significantly different between the strains. Iah1 mRNA levels in the liver, kidney, and lung were significantly higher in A/J-12(SM) mice than in A/J mice. The hepatic Iah1 mRNA level in A/J-12(SM) mice was 3.2-fold higher than that in A/J mice. To examine the effect of Iah1 on hepatic lipid metabolism, we constructed a stable cell line expressing the mouse Iah1 protein in mouse hepatoma Hepa1-6 cells. Overexpression of Iah1 in Hepa1-6 cells suppressed the mRNA levels of Cd36 and Dgat2, which play important roles in triglyceride synthesis and lipid metabolism.ConclusionsThese results demonstrated that Fl1sa on the proximal region of chromosome 12 affected fatty liver in mice on a high-fat diet. Iah1 (isoamyl acetate-hydrolyzing esterase 1 homolog) was identified as one of the candidate genes for Fl1sa. This study revealed that the mouse Iah1 gene regulated the expression of genes related to lipid metabolism in the liver.
| S-EPMC4895971 | biostudies-literature
Project description:BackgroundA highly significant quantitative trait locus (QTL) on chromosome 4 that influenced alcohol preference was identified by analyzing crosses between the iP and iNP rats. Congenic strains in which the iP chromosome 4 QTL interval was transferred to the iNP (NP.P) exhibited the expected increase in alcohol consumption compared with the iNP background strain. This study was undertaken to identify genes in the chromosome 4 QTL interval that might contribute to the differences in alcohol consumption between the alcohol-naïve congenic and background strains.MethodsRNA from 5 brain regions from each of 6 NP.P and 6 iNP rats was labeled and analyzed separately on an Affymetrix Rat Genome 230 2.0 microarray to look for both cis-regulated and trans-regulated genes. Expression levels were normalized using robust multi-chip average (RMA). Differential gene expression was validated using quantitative real-time polymerase chain reaction. Five individual brain regions (nucleus accumbens, frontal cortex, amygdala, hippocampus, and striatum) were analyzed to detect differential expression of genes within the introgressed QTL interval, as well as genes outside that region. To increase the power to detect differentially expressed genes, combined analyses (averaging data from the 5 discrete brain regions of each animal) were also carried out.ResultsAnalyses within individual brain regions that focused on genes within the QTL interval detected differential expression in all 5 brain regions; a total of 35 genes were detected in at least 1 region, ranging from 6 genes in the nucleus accumbens to 22 in the frontal cortex. Analysis of the whole genome detected very few differentially expressed genes outside the QTL. Combined analysis across brain regions was more powerful. Analysis focused on the genes within the QTL interval confirmed 19 of the genes detected in individual regions and detected 15 additional genes. Whole genome analysis detected 1 differentially expressed gene outside the interval.ConclusionsCis-regulated candidate genes for alcohol consumption were identified using microarray profiling of gene expression differences in congenic animals carrying a QTL for alcohol preference.
| S-EPMC4455872 | biostudies-literature
Project description:Extensive genetic and genomic studies of the relationship between alcohol drinking preference and withdrawal severity have been performed using animal models. Data from multiple such publications and public data resources have been incorporated in the GeneWeaver database with >60,000 gene sets including 285 alcohol withdrawal and preference-related gene sets. Among these are evidence for positional candidates regulating these behaviors in overlapping quantitative trait loci (QTL) mapped in distinct mouse populations. Combinatorial integration of functional genomics experimental results revealed a single QTL positional candidate gene in one of the loci common to both preference and withdrawal. Functional validation studies in Ap3m2 knockout mice confirmed these relationships. Genetic validation involves confirming the existence of segregating polymorphisms that could account for the phenotypic effect. By exploiting recent advances in mouse genotyping, sequence, epigenetics, and phylogeny resources, we confirmed that Ap3m2 resides in an appropriately segregating genomic region. We have demonstrated genetic and alcohol-induced regulation of Ap3m2 expression. Although sequence analysis revealed no polymorphisms in the Ap3m2-coding region that could account for all phenotypic differences, there are several upstream SNPs that could. We have identified one of these to be an H3K4me3 site that exhibits strain differences in methylation. Thus, by making cross-species functional genomics readily computable we identified a common QTL candidate for two related bio-behavioral processes via functional evidence and demonstrate sufficiency of the genetic locus as a source of variation underlying two traits.
| S-EPMC4125407 | biostudies-literature
Project description:The goal of this study was to identify candidate genes that may influence alcohol consumption by comparing gene expression in 5 brain regions of alcohol-naïve iP and P.NP rats. Background: Selectively bred P (alcohol preferring) and NP (alcohol non-preferring) rats differ greatly in alcohol preference, in part due to a highly significant QTL on chromosome 4. Reciprocal congenic strains in which the iP chromosome 4 QTL interval was transferred to the iNP background (NP.P) and the iNP chromosome 4 QTL was transferred to the iP background (P.NP) exhibited alcohol consumption scores that correlated with the introgressed interval. The goal of this study was to identify candidate genes that may influence alcohol consumption by comparing gene expression in 5 brain regions of alcohol-naïve iP and P.NP rats. Methods: RNA from the amygdala, nucleus accumbens, hippocampus, caudate putamen, and frontal cortex from each of 8 iP and 8 P.NP rats was labeled and analyzed on Affymetrix Rat Genome 230 2.0 microarrays. Expression levels were normalized using robust multi-chip average (RMA), and differential gene expression was measured in individual brain regions and in the average of the five brain regions. Differential gene expression was validated using quantitative real-time PCR. Meta-analysis was applied to compare microarray data from this experiment with data from the reciprocal congenic strains NP.P vs. iNP (Carr et al, 2007). Results: We detected between 72 (nucleus accumbens) and 89 (hippocampus) cis-regulated probe sets within the QTL that significantly differed between the strains in the five brain regions. There was significant overlap among the regions; 157 cis-regulated probe sets were detected in at least one brain region, of which 104 showed differential expression in more than one region. Fewer trans-regulated probe sets were detected, ranging from 7 in the amygdala to 54 in the caudate putamen, and most of these differed in only one region; only 10 of the 85 trans-regulated probe sets differed in more than one region. To increase the power to detect differentially expressed genes, data from the five discrete brain regions of each animal were averaged; in this analysis we detected 141 cis-regulated probe sets and 207 trans-regulated probe sets. Meta-analysis comparing the present results from iP vs. P.NP rats with an earlier experiment that used the reciprocal congenic NP.P vs. iP demonstrated that 74 cis-regulated probe sets were differentially expressed in the same direction and with a consistent magnitude of difference in both experiments. No consistent trans-regulated probe sets were identified. Conclusions: Cis-regulated candidate genes for alcohol consumption that lie within the chromosome 4 QTL were identified and confirmed by meta-analysis with the reciprocal congenic NP.P vs iNP study. These genes are strong candidates for producing the difference in alcohol preference and consumption between the iP and iNP rats. There was little evidence for consistent trans-acting effects. Keywords: comparison of gene expression profiles for strain1 (P rat) vs. strain2 (P.NP rat)
2009-12-31 | GSE15415 | GEO
Project description:The goal of this study was to identify candidate genes that may influence alcohol consumption by comparing gene expression in 5 brain regions of alcohol-naïve iP and P.NP rats. Background: Selectively bred P (alcohol preferring) and NP (alcohol non-preferring) rats differ greatly in alcohol preference, in part due to a highly significant QTL on chromosome 4. Reciprocal congenic strains in which the iP chromosome 4 QTL interval was transferred to the iNP background (NP.P) and the iNP chromosome 4 QTL was transferred to the iP background (P.NP) exhibited alcohol consumption scores that correlated with the introgressed interval. The goal of this study was to identify candidate genes that may influence alcohol consumption by comparing gene expression in 5 brain regions of alcohol-naïve iP and P.NP rats. Methods: RNA from the amygdala, nucleus accumbens, hippocampus, caudate putamen, and frontal cortex from each of 8 iP and 8 P.NP rats was labeled and analyzed on Affymetrix Rat Genome 230 2.0 microarrays. Expression levels were normalized using robust multi-chip average (RMA), and differential gene expression was measured in individual brain regions and in the average of the five brain regions. Differential gene expression was validated using quantitative real-time PCR. Meta-analysis was applied to compare microarray data from this experiment with data from the reciprocal congenic strains NP.P vs. iNP (Carr et al, 2007). Results: We detected between 72 (nucleus accumbens) and 89 (hippocampus) cis-regulated probe sets within the QTL that significantly differed between the strains in the five brain regions. There was significant overlap among the regions; 157 cis-regulated probe sets were detected in at least one brain region, of which 104 showed differential expression in more than one region. Fewer trans-regulated probe sets were detected, ranging from 7 in the amygdala to 54 in the caudate putamen, and most of these differed in only one region; only 10 of the 85 trans-regulated probe sets differed in more than one region. To increase the power to detect differentially expressed genes, data from the five discrete brain regions of each animal were averaged; in this analysis we detected 141 cis-regulated probe sets and 207 trans-regulated probe sets. Meta-analysis comparing the present results from iP vs. P.NP rats with an earlier experiment that used the reciprocal congenic NP.P vs. iP demonstrated that 74 cis-regulated probe sets were differentially expressed in the same direction and with a consistent magnitude of difference in both experiments. No consistent trans-regulated probe sets were identified. Conclusions: Cis-regulated candidate genes for alcohol consumption that lie within the chromosome 4 QTL were identified and confirmed by meta-analysis with the reciprocal congenic NP.P vs iNP study. These genes are strong candidates for producing the difference in alcohol preference and consumption between the iP and iNP rats. There was little evidence for consistent trans-acting effects. Keywords: comparison of gene expression profiles for strain1 (P rat) vs. strain2 (P.NP rat) 40 samples each of P and P.NP (8 animals each of P and P.NP. 5 brain regions)
2009-12-30 | E-GEOD-15415 | biostudies-arrayexpress
Project description:Linkage studies of alcoholism have implicated several chromosome regions, leading to the successful identification of susceptibility genes, including ADH4 and GABRA2 on chromosome 4. Quantitative endophenotypes that are potentially closer to gene action than clinical endpoints offer a means of obtaining more refined linkage signals of genes that predispose alcohol use disorders (AUD). In this study we examine a self-reported measure of the maximum number of drinks consumed in a 24-hr period (abbreviated Max Drinks), a significantly heritable phenotype (h(2) = 0.32 ± 0.05; P = 4.61 × 10(-14)) with a strong genetic correlation with AUD (ρg = 0.99 ± 0.13) for the San Antonio Family Study (n = 1,203). Genome-wide SNPs were analyzed using variance components linkage methods in the program SOLAR, revealing a novel, genome-wide significant QTL (LOD = 4.17; P = 5.85 × 10(-6)) for Max Drinks at chromosome 6p22.3, a region with a number of compelling candidate genes implicated in neuronal function and psychiatric illness. Joint analysis of Max Drinks and AUD status shows that the QTL has a significant non-zero effect on diagnosis (P = 4.04 × 10(-3)), accounting for 8.6% of the total variation. Significant SNP associations for Max Drinks were also identified at the linkage region, including one, rs7761213 (P = 2.14 × 10(-4)), obtained for an independent sample of Chinese families. Thus, our study identifies a potential risk locus for AUD at 6p22.3, with significant pleiotropic effects on the heaviness of alcohol consumption that may not be population specific.
| S-EPMC4172449 | biostudies-literature
Project description:Identification of genetic factors that modify complex traits is often complicated by gene-environment interactions that contribute to the observed phenotype. In model systems, the phenotypic outcomes quantified are typically traits that maximize observed variance, which in turn, should maximize the detection of quantitative trait loci (QTL) in subsequent mapping studies. However, when the observed trait is dependent on multiple interacting factors, it can complicate genetic analysis, reducing the likelihood that the modifying mutation will ultimately be found. Alternatively, by focusing on intermediate phenotypes of a larger condition, we can reduce a model's complexity, which will, in turn, limit the number of QTL that contribute to variance. We used a novel method to follow angiogenesis in mice that reduces environmental variance by measuring endothelial cell growth from culture of isolated skin biopsies that varies depending on the genetic source of the tissue. This method, in combination with a backcross breeding strategy, is intended to reduce genetic complexity and limit the phenotypic effects to fewer modifier loci. We determined that our approach was an efficient means to generate recombinant progeny and used this cohort to map a novel s.c. angiogenesis QTL to proximal mouse chromosome (Chr.) 8 with suggestive QTL on Chr. 2 and 7. Global mRNA expression analysis of samples from parental reference strains revealed β-defensins as potential candidate genes for future study.
| S-EPMC4365986 | biostudies-literature
Project description:This investigation examines the genetic sources of marked variation in cone photoreceptor number among inbred lines of mice, identifying candidate genes that may control the proliferation, differentiation, or survival of this neuronal population.Cone photoreceptor populations were counted in C57BL/6J (B6/J) and A/J strains, and 26 recombinant inbred (RI) strains derived from them. Eyes from RI strains were also collected for microarray analysis. Quantitative trait locus (QTL) analysis was carried out by simple and composite interval mapping and validated using a consomic line. Candidate genes were evaluated based on genetic variance between the parental strains and analysis of gene expression. Expression data, deposited in GeneNetwork (www.GeneNetwork.org), were used to generate a coexpression network of established cone photoreceptor genes as a reference standard.B6/J has 70% more cone photoreceptors than A/J. A significant QTL was mapped to chromosome 10 (Chr 10) and confirmed using B6.A<10> mice. Of 19 positional candidate genes, one-the myeloblastosis oncogene (Myb)-stood out. Myb has a potentially damaging missense mutation, high retinal expression, and a known role in cell proliferation. The ectonucleotide pyrophosphatase/phosphodiesterase 1 gene (Enpp1) was a second strong candidate, with an expression pattern that covaried with cone photoreceptors and that was differentially expressed between the parental strains. Enpp1 and several other candidate genes covaried with multiple genes within the cone photoreceptor gene network.The mouse retina shows marked variation in cone photoreceptor number, some of which must be controlled by polymorphisms in a gene or genes on Chr 10.
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