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[The methodological aspects of assessing the mutagenic background and genetic risk for man and the biota from the action of mutagenic ecological factors].

Methodology of the assessment of territory state for mutagenic background and genetic risk was proposed. It is based on analysis of results of cytogenetic monitoring of high-sensitive bioindicators and children populations as well as an analysis of statistic data on hereditary and ecology-dependent diseases in human populations. Methodology has been tested under the conditions of Dnepropetrovsk Province, that allowed to specify areas of increased genetic risk.

Adult↗
PubMed1994

Lethality of PE2 incorporation into Sindbis virus can be suppressed by second-site mutations in E3 and E2.

Sindbis virions contain two glycoproteins, E1 and E2. E2 is produced initially as a precursor, PE2, from which the amino-terminal 64 amino acids are cleaved by a cellular protease at a late stage in virion maturation. A mutation at E2 position 1 (Arg to Asn) was placed into Sindbis virus AR339 by site-directed mutagenesis of a full-length AR339 cDNA clone, pTRSB, to produce pTRSB-N. The mutation created a signal for N-linked glycosylation immediately adjacent to the PE2 cleavage signal. Virions derived from pTRSB-N were glycosylated at E2 position 1, and they quantitatively incorporated PE2 in place of E2. When pTRSB-N transcripts were electroporated into BHK-21 cells, TRSB-N particles were released with nearly normal efficiency; however, the specific infectivity of TRSB-N particles was very low. Analysis of seven infectious revertants of TRSB-N revealed that reversion was linked to (i) mutations that eliminated the signal for N-linked glycosylation and thus restored the PE2 cleavage phenotype or (ii) conservation of the PE2 cleavage defect combined with incorporation of suppressor mutations in E3 or E2. The genotype of each revertant was reconstructed in the genetic background of TRSB-N, and each reverting mutation also was replaced individually into the genetic background of wild-type virus (TRSB). Each PE2-containing revertant was attenuated in newborn CD-1 mice and replicated poorly in cultured mosquito cells (C6/36). Reverting mutations in the genetic background of TRSB did not reduce virulence in mice or growth in mosquito cells, suggesting that the phenotypes of attenuation in mice and reduced growth in mosquito cells were linked to failure of PE2 cleavage and not to the reverting mutations themselves.

Amino Acid Sequence↗
PubMed2004

Pervasive joint influence of epistasis and plasticity on mutational effects in Escherichia coli.

The effects of mutations on phenotype and fitness may depend on the environment (phenotypic plasticity), other mutations (genetic epistasis) or both. Here we examine the fitness effects of 18 random insertion mutations in E. coli in two resource environments and five genetic backgrounds. We tested each mutation for plasticity and epistasis by comparing its fitness effects across these ecological and genetic contexts. Some mutations had no measurable effect in any of these contexts. None of the mutations had effects on phenotypic plasticity that were independent of genetic background. However, half the mutations had epistatic interactions such that their effects differed among genetic backgrounds, usually in an environment-dependent manner. Also, the pattern of mutational effects across backgrounds indicated that epistasis had been shaped primarily by unique events in the evolutionary history of a population rather than by repeatable events associated with shared environmental history.

Epistasis, Genetic↗
PubMed2005

Introductory guide to the statistics of molecular genetics.

BACKGROUND: This introductory guide presents the main two analytical approaches used by molecular geneticists: linkage and association. METHODS: Traditional linkage and association methods are described, along with more recent advances in methodologies such as those using a variance components approach. RESULTS: New methods are being developed all the time but the core principles of linkage and association remain the same. The basis of linkage is the transmission of a marker along with a disease within families, whereas association is based on the comparison of marker frequencies in case and control groups. CONCLUSIONS: It is becoming increasingly clear that effect sizes of individual markers on diseases and traits are likely to be very small. As such, much greater power is needed, and correspondingly greater sample sizes. Although non-replication is still a problem, molecular genetic studies in some areas such as attention deficit/hyperactivity disorder (ADHD) are starting to show greater convergence. Epidemiologists and other researchers with large well-characterized samples will be well placed to use these methods. Inter-disciplinary studies can then ask far more interesting questions such as those relating to developmental, multivariate and gene-environment interaction hypotheses.

Epidemiologic Methods↗
PubMed2005

[Suicide attempt, psychopathology and genetics].

BACKGROUND: There is compelling evidence that suicidal behaviour has a heritable component and is associated with disturbances in serotonergic mechanisms. Thus genes coding for proteins of the serotonergic pathways are leading candidates for investigating possible associations. METHOD: We studied three serotonergic gene polymorphisms (5-HTTLPR S/L, TPH A779C, 5-HT1B G861C) in a sample of 114 unrelated suicide attempters (mainly non-violent methods), in 112 patients, 23 siblings and 56 healthy controls. Genotyping was done using polymerase chain reaction (PCR) based assays. The primary analyses compared allele and genotype frequencies between patients and controls and to test for presence of linkage disequilibrium using the family based association test (FBAT). The genotypes were further related to clinical characteristics and to psychological traits. RESULTS: There was a trend towards an increase in the L-allele frequency of the 5-HTTLPR in suicidal patients (p=0.066, OR=1,57, 95%CI 0,96-2,52). No other polymorphisms were associated with suicidal behaviour and the FBAT showed no excess transmission of any allele from parents to the offsprings. We found a slight reduction in "Novelty Seeking Scores" in patients having at least one S-allele (one-way ANOVA F=3,90, p=0.024). All the other traits were not related to any of the genotypes. CONCLUSION: Our data extend the evidence that genetic factors do not play a major role in non-violent suicidal behaviour. The 5-HTTLPR S/L variants may have an impact on personality traits.

Adult↗
PubMed2005

Serum immunoglobulin E levels in Israeli-Ethiopian children: environment and genetics.

BACKGROUND: Since 1984, several waves of Ethiopian immigrants have settled in Israel. On arrival they were found to be highly infected with intestinal parasites and to have increased serum immunoglobulin E and eosinophilia. OBJECTIVES: To study serum IgE levels in Ethiopian children growing up in the environment of Israel. METHODS: We assessed four groups of children of Ethiopian origin: a) adolescents examined on their arrival to Israel (group 1, n=11); b) adolescents born in Ethiopia and living in Israel for more than 7 years (group 2, n=10); c) children of Ethiopian origin born in Israel, without a history of allergy or asthma (group 3, n=15); and d) asthmatic children of Ethiopian origin born in Israel (group 4, n=8). A thorough clinical interview and examination as well as laboratory work up (including serum IgE levels, stool parasites and absolute eosinophil count) were performed. RESULTS: Group 1 (11 newly arrived Ethiopian adolescents) had a mean eosinophil count of 688 cells/ml (0-1739) and a mean serum IgE of 1043 IU/ml (253-2932), P< 0.0009 as compared to group 2. Helminthic parasites were observed in 8/11 individuals; after 1 year of follow-up and anti-parasitic treatment, serum IgE levels did not change significantly. Group 2 (10 Ethiopian born adolescents living in Israel for on average 10 years, 7-15 years) had a normal leukocyte count, MEC 192 cells/ml (range 54-289), serum IgE 142 IU/ml (range 14-399 IU/ml) and no parasites in stool. Group 3 (15 Ethiopian children born in Israel) had a normal leukocyte count, MEC 128 cells/ml (0-324), serum IgE 55 IU/ml (7-189 IU/ml), similar to age-matched Israeli controls. In group 4 (8 Israeli born children of Ethiopian descent diagnosed with asthma), serum IgE showed significant elevation compared to Israeli age-matched asthmatic children (P< 0.005). CONCLUSIONS: High levels of IgE found in Ethiopian children on arrival to Israel declined to Israeli control levels after several years of living in the new environment. Ethiopian children born in Israel had normal levels of IgE, suggesting that environment is the main factor affecting IgE levels in this population. Israeli born Ethiopian children with asthma had significantly increased serum IgE levels compared to asthmatics of Israeli origin. These findings suggest that both environmental and genetic factors determine the level of serum IgE in these children.

Adolescent↗
PubMed2001

The studies of hemoglobinopathies and thalassemia in China--the experiences in Shanghai Institute of Medical Genetics.

BACKGROUND: In the past two decades, a large-scale survey of hemoglobinopathies and thalassemia was carried out in mainland China, involving nearly one million people in 28 provinces. The incidences of hemoglobin (Hb) variants, alpha-thalassemia and beta-thalassemia were 0.33%, 2.64% and 0.66%, respectively. The chemical structural analysis identified 67 Hb variants. Among them, 20 are new variants. The analysis of the alpha-globin gene organization in 111 HbH patients showed 76 cases (68.5%) were of the deletion type, 8 had Hb Constant Spring and the other cases were of non-deletion type. The results of the molecular characterization of more than 200 beta-thalassemia alleles showed that the most common types of beta-thalassemia mutations in China are CD 41/42 (-4 bp), IVS-II-nt.654 C-->T, CD 17 A-->T, CD 71/72 (+A) and -28 A-->G. METHODS: To explore the simple method for molecular diagnosis of beta-thalassemia, multiplex allele-specific amplification (MAS-PCR) was used that could simultaneously detect the above five common types of beta-thalassemia mutations. RESULTS: Based on the molecular analysis of beta-thalassemia intermedia, beta-thalassemia homozygotes or compound heterozygotes combined with alpha-thalassemia, as well as the conjunctive abnormalities of beta-thalassemia heterozygote with triplicated haplotype of alpha-globin genes, were the most common cause of thalassemia intermedia in China. We also used the RT-PCR quantitation method to show that the most common beta-thalassemia allele, IVS-II-nt.654 C-->T, still produced a small amount (about 15%) of normally spliced beta-globin mRNA, therefore, causing beta+-thalassemia. In clinical trials of hydroxyurea (HU) treatment for beta-thalassemia patients, we found that HU may enhance the expression of the beta-globin gene in some patients, leading to an alleviation of clinical symptoms. In the studies of the reversal of aberrant splicing of IVS-II-nt.654 C-->T allele by the antisense approach, we constructed a mammalian expression vector that can produce an antisense RNA targeting against the aberrant splice sites of IVS-II-nt.654 C-->T pre-mRNA. CONCLUSIONS: The results indicated that the antisense RNA produced from the vector could efficiently suppress the aberrant splicing pattern and restore the correct splicing pathway in vitro and in vivo, leading to the improvement of globin chain biosynthesis in thalassemia cells.

China↗
PubMed2005

Prevalence of hyperhomocysteinemia in adult gluten-sensitive enteropathy at diagnosis: role of B12, folate, and genetics.

BACKGROUND & AIMS: Hyperhomocysteinemia, a risk factor for thrombosis, recurrent miscarriages, and osteoporosis, might derive from acquired folate and vitamin B 12 deficiencies and from a C677T mutation in methylene-tetrahydrofolate reductase (MTHFR) gene. Undiagnosed gluten-sensitive enteropathy (GSE) is associated with vitamin deficiencies, osteoporosis, and recurrent miscarriages. We evaluated the prevalence and the risk factors for hyperhomocysteinemia in patients with newly diagnosed GSE. METHODS: In this prospective study performed in a tertiary care setting, 40 consecutive subjects with newly diagnosed GSE were evaluated for homocysteine, folate, and vitamin B 12 levels and for C677T polymorphism. One hundred twenty sex- and age-matched healthy control subjects were studied. Nonparametric tests and multiple regression analysis were used to evaluate the risk factors in inducing hyperhomocysteinemia in the GSE population. RESULTS: Hyperhomocysteinemia was more frequent in GSE patients than in control subjects (8/40, 20.0% vs 7/120, 5.8%) (relative risk, 3.4; 95% confidence interval, 1.3-8.9), as well as folate deficiency (17/40, 42.5% vs 10/120, 8.3%) (relative risk, 5.1; 95% confidence interval, 2.5-10.2). Multiple regression analysis showed that folate and B 12 levels were independently and inversely associated with homocysteine levels, whereas homozygosity for the MTHFR thermolabile variant was not. The prevalence of MTHFR variant in GSE population was not different from that reported in racially comparable control groups. Gluten-free diet was able to normalize folate, vitamin B 12 , and homocysteine levels. CONCLUSIONS: Hyperhomocysteinemia is frequent in newly diagnosed GSE. Vitamin deficiencies caused by malabsorption are the most important determinants of this condition. Hyperhomocysteinemia might contribute to the occurrence of common complications of undiagnosed GSE.

Adult↗
PubMed2004

Role for thromboxane receptors in angiotensin-II-induced hypertension.

To evaluate the role of thromboxane in hypertension and its complications, we studied mice with targeted disruption of the TXA2 receptor gene in an angiotensin-II-dependent model of hypertension. To determine whether genetic background might alter the physiological actions of the TP receptor, we studied two lines of TP knockout (Tp-/-) mice with distinct genetic backgrounds (C57BL/6 and BALB/c). During chronic angiotensin II infusion (1000 ng/kg per minute x 28 days by subcutaneous osmotic pump), TP deficiency prevented mortality in the C57BL/6 background but not in the BALB/c strain. Chronic angiotensin II infusion also caused a rapid and significant increase in blood pressure in wild-type (WT) C57BL/6 and BALB/c animals, which was significantly attenuated in Tp-/- mice on either background. After 28 days of infusion, cardiac hypertrophy only occurred in the C57BL/6 strain: heart/body weight ratio increased by 57%+/-8% in WT mice compared with 17%+/-6.5% for the Tp-/- mice (P<0.01). Chronic angiotensin II infusion caused albuminuria only in the C57BL/6 strain, and TP deficiency did not alter its development. Cyclooxygenase-1 knockout mice also had attenuated blood pressure increase during chronic angiotensin II infusion, suggesting that cyclooxygenase-1 metabolites are involved in angiotensin-II-dependent hypertension. Thus, on the C57BL/6 background, TP receptors contribute to cardiac hypertrophy but not proteinuria. However, irrespective of genetic background, the TP receptor makes a robust contribution to the pathogenesis of angiotensin II-dependent hypertension.

Albuminuria↗
PubMed2003

Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: worldwide emergence.

Infections caused by community-acquired (CA)-methicillin--resistant Staphylococcus aureus (MRSA) have been reported worldwide. We assessed whether any common genetic markers existed among 117 CA-MRSA isolates from the United States, France, Switzerland, Australia, New Zealand, and Western Samoa by performing polymerase chain reaction for 24 virulence factors and the methicillin-resistance determinant. The genetic background of the strain was analyzed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The CA-MRSA strains shared a type IV SCCmec cassette and the Panton-Valentine leukocidin locus, whereas the distribution of the other toxin genes was quite specific to the strains from each continent. PFGE and MLST analysis indicated distinct genetic backgrounds associated with each geographic origin, although predominantly restricted to the agr3 background. Within each continent, the genetic background of CA-MRSA strains did not correspond to that of the hospital-acquired MRSA.

Bacterial Toxins↗
PubMed1989

The significance of genetic factors for thalidomide teratogenicity in the Norway rat.

Thalidomide teratogenicity was tested on a model based on the system of congenic strains of the laboratory rat, including the mutant allele lx, which determines the polydactyly-luxate syndrome. The phenotypic expression of the allele lx changes according to the genetic background of the carrier and also according to factors of the external environment. On a hybrid genetic background LEW/BN the allele lx acts as recessive, and heterozygotes +/lx are unaffected. In a number of experiments it was proved, however, that these hybrids (LEW/BN, +/lx) had an increased sensitivity to the induction of limb malformations (polydactyly, tibial hemimelia, oligodactyly) by various teratogens. Thalidomide was administered on the 12th day of pregnancy by the intraperitoneal route in a mixture of Tween 20 with saline (1:3) in doses of 25, 50 and 200 mg/kg to females with genetic background LEW that were purposely mated with males of the BN or BN.lx strains. The produced progeny had genotypes LEW/BN, +/+ or LEW/BN, +/lx. In offsprings that had in the genotype the mutant allele lx in a heterozygous condition (+/lx) preaxial polydactyly of hind limbs developed after all the thalidomide doses tested. This malformation occurred in 17 out of 18 litters, altogether in 97 out of 162 foetuses +/lx, i.e. in 59.9%. In the progeny without the mutant allele (genotype +/+) polydactyly did not develop in any of the 108 cases. Control foetuses +/+ the mothers of which had been administered only Tween 20 with saline remained unaffected, while in control foetuses +/lx polydactyly developed in 8.1% (3 cases). The result demonstrates thalidomide teratogenicity in the laboratory rat where it has not been proved unambiguously so far. The teratogenic effect is the outcome of the interaction of thalidomide with the mutant allele lx. At the same time there is emphasized the importance of the genotype of the experimental animals in the testing of teratogens.

Animals↗
PubMed2001

The 5-HT(1A) receptor knockout mouse and anxiety.

The 5-HT(1A) receptor has been implicated in the modulation of anxiety processes, mainly via pharmacological experiments. The recent production, in three independent research groups, of 5-HT(1A) receptor knockout (R KO) mice in three different genetic backgrounds (C57BL/6J, 129/Sv, Swiss-Webster) led to the intriguing finding that all mice, independent from the genetic background strain from which the null mutants were made, showed an "anxious" phenotype compared to corresponding wild-type mice. The present paper reviews the behavioral findings in these three KO lines and focuses on new findings in the 129/Sv-KO mice. These mice were more anxious or stress-prone only under specific conditions (high stress) and not as broadly as suggested from the initial studies. The 5-HT(1A) R KO made in the Swiss-Webster background displays disturbances in the GABA(A)-benzodiazepine (BZ) receptor system in the brain, including downregulation of GABA(A) alpha1 and alpha2 subunits in the amygdala. In contrast, the GABA(A)-BZ receptor system seems to function normally in the 5-HT(1A) R KO in the 129/Sv background suggesting that changes in the GABA(A)-BZ receptor system may not be a prerequisite for anxiety but rather could have a modifying effect on this phenotype. It can be concluded that the constitutive absence of the 5-HT(1A) receptor gene and receptor leads to a more "anxious" mouse, dependent on the stress level but independent from the strain. Depending on the genetic background, this null mutation may be associated with changes in GABA(A)-ergic neurotransmission. It is as yet unclear which mechanisms are involved in this intriguing differentiation.

Animals↗
PubMed1993

Genetic control of drug-induced recovery from murine visceral leishmaniasis.

The influence of host genetic background on the response of Leishmania donovani-infected mice to chemotherapy was studied using the H-2d and H-2b haplotypes on a BALB or a B10 genetic background. Animals were treated with free or liposomal sodium stibogluconate and parasite burdens in the liver, spleen and bone marrow were assessed. In all the mouse strains and their congenic derivatives examined, the liver responded best to therapy regardless of drug formulation, whilst the spleen and the bone marrow respectively were increasingly less responsive to chemotherapy. Treatment with free drug was more effective in congenic mice carrying the H-2b haplotype than in those carrying the H-2d haplotype and in mice carrying the same H-2 haplotype, animals from a BALB background were better responders than those from a B10 genetic background. Liposomal drug was more effective than free drug treatment in all four mouse strains and produced a similar significant suppression (> 99%, P < 0.001) in liver parasite burdens to that obtained using a six times greater free drug dose. This liposomal drug dose was more effective than free drug in reducing bone marrow parasite burdens in all four mouse strains and equally (BALB/c mice) or more effective (P < 0.01, BALB/B, B10 and B10.D2 strains) in reducing spleen parasite numbers. Liposomal dependent influences apparent using free sodium stibogluconate. These results are discussed in relation to the genetic factors which are known to control the course of L. donovani infection in mice.

Animals↗
PubMed2004

Application of chromosomal substitution techniques in gene-function discovery.

A consomic rat strain is one in which an entire chromosome is introgressed into the isogenic background of another inbred strain using marker assisted selection. The development and initial physiologic screening of two inbred consomic rat panels on two genetic backgrounds (44 strains) is well underway. The primary uses of consomic strains are: (1) to assign traits and quantitative trait loci (QTL) to chromosomes by surveying the panel of strains with substituted chromosomes; (2) to rapidly develop congenic strains over a narrow region using several approaches described in this review and perform F2 linkage studies to positionally locate QTL in a fixed genetic background. In addition, consomic strains overcome many of the problems encountered with segregating crosses where, even if linkage is found, each individual in the cross is genetically unique and the combination of genes cannot be reproduced or studied in detail. Consomic strains provide greater statistical power to detect linkage than traditional F2 crosses because of their fixed genetic backgrounds, and can produce sufficient numbers of genetically identical rats to validate the relationship between a trait and a particular chromosome. These strains allow studies to be performed in a replicative or longitudinal manner to elucidate in greater detail the sequential changes responsible for the observed phenotypes of these animals, and they enable one to assess the impact of a causal gene region in a genome by allowing comparisons of the effect of replacement of a specific chromosome upon a disease susceptible or resistant genomic background. Consomics can be used to quickly develop multiple chromosome substitution models to investigate gene-gene interactions of complex traits or diseases. Finally, they often provide the best available inbred control strain for particular physiological comparisons with the inbred parental strains. Consomic rat strains are proving to be a unique scientific resource that greatly extends our understanding of genes and complex normal and pathological function.

Animals↗
PubMed2006

Cumulative mutations affecting sterol biosynthesis in the yeast Saccharomyces cerevisiae result in synthetic lethality that is suppressed by alterations in sphingolipid profiles.

UPC2 and ECM22 belong to a Zn(2)-Cys(6) family of fungal transcription factors and have been implicated in the regulation of sterol synthesis in Saccharomyces cerevisiae and Candida albicans. Previous reports suggest that double deletion of these genes in S. cerevisiae is lethal depending on the genetic background of the strain. In this investigation we demonstrate that lethality of upc2Delta ecm22Delta in the S288c genetic background is attributable to a mutation in the HAP1 transcription factor. In addition we demonstrate that strains containing upc2Delta ecm22Delta are also inviable when carrying deletions of ERG6 and ERG28 but not when carrying deletions of ERG3, ERG4, or ERG5. It has previously been demonstrated that UPC2 and ECM22 regulate S. cerevisiae ERG2 and ERG3 and that the erg2Delta upc2Delta ecm22Delta triple mutant is also synthetically lethal. We used transposon mutagenesis to isolate viable suppressors of hap1Delta, erg2Delta, erg6Delta, and erg28Delta in the upc2Delta ecm22Delta genetic background. Mutations in two genes (YND1 and GDA1) encoding apyrases were found to suppress the synthetic lethality of three of these triple mutants but not erg2Delta upc2Delta ecm22Delta. We show that deletion of YND1, like deletion of GDA1, alters the sphingolipid profiles, suggesting that changes in sphingolipids compensate for lethality produced by changes in sterol composition and abundance.

Candida albicans↗
PubMed2006

[Current concepts in the genetics of hereditary and sporadic colorectal cancer and the role of genetics in patient management. Hereditary colorectal cancers].

Colorectal cancer (CRC) is the second leading cause of mortality of malignant diseases in Hungary and according to the incidence and prevalence of CRC Hungary is second among European countries. Hence, it is of outstanding interest to know the current concepts on pathogenesis and genetical background of CRC, as well as incorporate this knowledge in the everyday practice. In the first part of the review authors address the genetic background of hereditary colorectal cancer syndromes. In fact, a positive family history may be found in 20-30% and genetically defined trait (e.g. familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC) and Peutz-Jeghers-syndrome (PJS)) is responsible for 3-5% of all colon cancers. Germline mutations of tumor suppressor gene, APC (5q21) are found in 70-90% of the cases. Until now more than 300 mutations were identified. Though a typical mutation was not found, the location of the mutation is associated to the clinical phenotype and prognosis. Of note, beside APC mutations, biallelic mutations of the MYH gene may be found in a subset of individuals with FAP. The diagnosis of HNPCC is based on family history and the presence of Amsterdam I-Il or Bethesda criteria. The genetic background and clinical phenotype of the syndrome is heterogeneous. Mutations of different mismatch repair genes (mainly hMLH1 or hMSH2) may be identified in most cases. Genetic testing is advised in first degree relatives of FAP patients, if genetic testing is not available colonoscopic surveillance should be done starting at the age of 10-12 years. Due to the high number of mutation genetic testing is difficult in HNPCC families and colonoscopic screening should be advised to affected families.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Genetic and environmental modifiers of Alzheimer's disease phenotypes in the mouse.

As a group, strains of laboratory mice carrying Alzheimer's disease (AD)-related transgenes are currently the most widely studied animal models of AD. Many AD mouse models carrying the same or similar transgene constructs demonstrate strikingly different phenotypic responses to transgene expression, mimicking the apparent genetic complexity of AD pathogenesis seen in the human population. Genetic differences between the numerous mouse model strains used for AD research can significantly affect correct interpretation and cross-comparison of experimental findings, making genetic background an important consideration for all work in mouse models of AD. Furthermore, because of the potential for discovering novel genetic modifiers of AD pathogenesis, the effects of genetic background on AD phenotypes in the mouse can prove a worthwhile subject of study in their own right. This review discusses the implications of genetic modifiers for mouse and human AD research, and summarizes recent findings identifying significant roles for genetic background in modifying important phenotypes in AD mouse models, including premature death, amyloid deposition, tau hyperphosphorylation, and responsiveness to environmental or treatment interventions.

Alzheimer Disease↗
PubMed2016

Androgen-sensitive hypertension associated with soluble guanylate cyclase-&#x3b1;1 deficiency is mediated by 20-HETE.

Dysregulated nitric oxide (NO) signaling contributes to the pathogenesis of hypertension, a prevalent and often sex-specific risk factor for cardiovascular disease. We previously reported that mice deficient in the &#x3b1;1-subunit of the NO receptor soluble guanylate cyclase (sGC&#x3b1;1 (-/-) mice) display sex- and strain-specific hypertension: male but not female sGC&#x3b1;1 (-/-) mice are hypertensive on an 129S6 (S6) but not a C57BL6/J (B6) background. We aimed to uncover the genetic and molecular basis of the observed sex- and strain-specific blood pressure phenotype. Via linkage analysis, we identified a suggestive quantitative trait locus associated with elevated blood pressure in male sGC&#x3b1;1 (-/-)S6 mice. This locus encompasses Cyp4a12a, encoding the predominant murine synthase of the vasoconstrictor 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE). Renal expression of Cyp4a12a in mice was associated with genetic background, sex, and testosterone levels. In addition, 20-HETE levels were higher in renal preglomerular microvessels of male sGC&#x3b1;1 (-/-)S6 than of male sGC&#x3b1;1 (-/-)B6 mice. Furthermore, treating male sGC&#x3b1;1 (-/-)S6 mice with the 20-HETE antagonist 20-hydroxyeicosa-6(Z),15(Z)-dienoic acid (20-HEDE) lowered blood pressure. Finally, 20-HEDE rescued the genetic background- and testosterone-dependent impairment of acetylcholine-induced relaxation in renal interlobar arteries associated with sGC&#x3b1;1 deficiency. Elevated Cyp4a12a expression and 20-HETE levels render mice susceptible to hypertension and vascular dysfunction in a setting of sGC&#x3b1;1 deficiency. Our data identify Cyp4a12a as a candidate sex-specific blood pressure-modifying gene in the context of deficient NO-sGC signaling.

Androgens↗