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PubMed2006

Identification, prevalence and population structure of non-typable Streptococcus pneumoniae in carriage samples isolated from preschoolers attending day-care centres.

The authors aimed to get insights into the population structure of non-(sero)typable pneumococci (NTPn), a specific group of natural atypical pneumococci whose identification is often difficult, and which has remained insufficiently studied. A total of 265 presumptive NTPn, isolated between 1997 and 2003 from the nasopharynx of children, were characterized. Strains were confirmed to be pneumococci on the basis of bile solubility, and PCR detection or Southern blotting hybridization of lytA and psaA, genes ubiquitous in this species. Multilocus sequence typing (MLST) was used to exclude two isolates that gave ambiguous results. Non-typability was confirmed by the Quellung reaction using Omniserum. A total of 213 isolates were considered to be true NTPn. The molecular analysis of the true NTPn by PFGE and MLST showed that this population was genetically diverse, although a dominant cluster, accounting for 66 % of the isolates, was identified. Antimicrobial resistance was observed in most genetic backgrounds, and multidrug resistance to penicillin, erythromycin, clindamycin, tetracycline and sulfamethoxazole-trimethoprim was associated with strains belonging to the dominant cluster. Comparison with PFGE fingerprints and sequence types of large collections of serotypable strains showed that the genetic backgrounds of all but two NTPn were different from those found in serotypable strains. In addition, we found that NTPn strains with similar genetic backgrounds to those identified in our study had been isolated from disease sources in other countries. These observations seem to indicate that NTPn have diverse genetic backgrounds and may have evolved as a distinct group of pneumococcal isolates.

Anti-Bacterial Agents↗
PubMed2005

Assembling complex genotypes to resist Fusarium in wheat (Triticum aestivum L.).

Fusarium head blight of wheat is a major deterrent to wheat production world-wide. The genetics of FHB resistance in wheat are becoming clear and there is a good understanding of the genome location of FHB resistance QTL from different sources such as Sumai3, Wuhan, Nyubai and Frontana. All the components needed for assembling complex genotypes through large-scale molecular breeding experiments are now available. This experiment used high throughput microsatellite genotyping and half-seed analysis to process four independent crosses through a molecular breeding strategy to introduce multiple pest resistance genes into Canadian wheat. This included two backcrosses and selection for a total of six FHB resistance QTL, orange blossom wheat midge resistance (Sm1) and leaf rust resistance (Lr21). In addition, the fixation of the elite genetic background was monitored with 45-76 markers to accelerate restoration of the genetic background at each backcross. The strategy resulted in 87% fixation of the elite genetic background on average at the BC2F1 generation and successfully introduced all of the chromosome segments containing FHB, Sm1 and Lr21 resistance genes. The molecular breeding strategy was completed in 25 months, at an equal pace to conventional crossing and selection of spring wheat.

Breeding↗
PubMed2025

Investigating the genomic landscape of mouse models of breast cancer metastasis.

Metastasis remains a major cause of cancer mortality. AbstractThis study, expanding upon previous findings in the MMTV-PyMT model, investigated four independent mouse models, representing luminal (MMTV-PyMT, MMTV-Myc), HER2-amplified (MMTV-Her2) and triple negative (C3(1)TAg) breast cancer subtypes. Consistent with previous results, limited evidence for metastasis-associated somatic point mutations was found for all models. We also found that oncogenic drivers significantly influenced the number and size of metastasis-specific copy number variations (MSCNVs), but common driver-independent MSCNVs were rare. Furthermore, analyzing a cohort with varying genetic backgrounds while maintaining a constant oncogenic driver (PyMT) revealed that genetic background profoundly impacts MSCNVs. Transcriptome analysis demonstrated that oncogenic drivers strongly shaped metastasis-specific gene expression (MSGE), with each driver exhibiting distinct expression profiles. In contrast, MSGE in the PyMT-F1 cohort was more variable across strains. Despite the diversity of MSCNV and MSGE, functional analysis revealed that both mechanisms converge on the modulation of key cellular processes, including immune responses, metabolism, and extracellular matrix interactions. These findings emphasize the complex interplay between oncogenic drivers and genetic background in shaping the genomic and transcriptional landscapes of metastatic lesions.

Journal Article↗
PubMed2004

Phenotypic variation resulting from a deficiency of epidermal growth factor receptor in mice is caused by extensive genetic heterogeneity that can be genetically and molecularly partitioned.

The timing of lethality caused by homozygosity for a null allele of the epidermal growth factor receptor (Egfrtm1Mag) in mice is strongly dependent on genetic background. Initial attempts to genetically map background modifiers using Swiss-derived, outbred CD-1 mice were unsuccessful. To investigate the genetic architecture contributing to survival of Egfrtm1Mag homozygous embryos, the genetic variability segregating within the outbred population was partitioned by surveying viability of Egfrtm1Mag mutants using intercrosses between 129S6/SvEvTAC-Egfrtm1Mag and nine Swiss-derived, inbred strains: ALR/LtJ, ALS/LtJ, APN, APS, ICR/HaRos, NOD/LtJ, NON/LtJ, SJL/J, and SWR/J. The observations showed that these strains support varying levels of survival of Egfrtm1Mag homozygous embryos, suggesting that genetic heterogeneity within the CD-1 stock contributed to the original lack of Egfrtm1Mag modifier detection. Similar to the Swiss-derived intercrosses, nine congenic strains, derived from 129S6/SvEvTAC, AKR/J, APN, BALB/cJ, BTBR-T+ tf/tf, C3H/HeJ, C57BL/6J, DBA/2J, and FVB/NJ inbred backgrounds, also supported varying levels of survival of Egfrtm1Mag mutants. By intercrossing the congenic lines to create hybrid F1 embryos, different genetic backgrounds were found to have complementary modifiers. Analysis of the congenic lines argues against heterosis of outbred backgrounds contributing to Egfrtm1Mag phenotypic variability. A detailed analysis of the crosses suggests that modifiers function at three distinct stages of development. One class of modifiers supports survival of Egfrtm1Mag homozygous embryos to mid-gestation, another class supports development through the mid-gestation transition from yolk-sac to placental-derived nutrient sources, and a third class supports survival through later stages of gestation. Data from microarray analysis using RNA from wild-type and Egfrtm1Mag mutant placentas support the existence of extensive genetic heterogeneity and suggest that it can be molecularly partitioned. This method should be generally useful to partition heterogeneity contributing to other complex traits.

Animals↗
PubMed2005

Effects of the rd1 mutation and host strain on hippocampal learning in mice.

Many of the inbred mouse strains commonly used in biomedical research are homozygous for the rd1 mutation of the Pde6b gene, which causes retinal degeneration. To dissociate the behavioural effects of rd1 homozygosity from those of the genetic background of the host strain in the most widely used paradigms for evaluating the cognitive abilities of mice, two rd1 homozygous strains (C3H/HeJ and CBA/J) were compared with two Pde6b wild-type strains, each possessing a genetic background identical (C3A.BLiA-Pde6b+/J) or very similar (CBA/CaJ) to that of its rd1 homozygous relative. In the fear conditioning procedure, the presence of the rd1 mutation had no effect on performance at any stage, as the superior contextual learning of the CBA/J and CBA/CaJ strains could be explained by genetic background effects alone. In the Morris water maze, only the Pde6b wild-type C3A.BLiA-Pde6b+/J and CBA/CaJ strains were able to demonstrate spatial learning. The study thus demonstrates how retinal degeneration and genetic background have different effects in these two tests of hippocampus-dependent learning and memory.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1999

Dystonia associated with mutation of the neuronal sodium channel Scn8a and identification of the modifier locus Scnm1 on mouse chromosome 3.

The mouse mutant medJ contains a splice site mutation in the neuronal sodium channel Scn8a that results in a very low level of expression. On a C57BL/6J genetic background, medJ homozygotes exhibit progressive paralysis and juvenile lethality. The C3H genetic background has an ameliorating effect, producing viable adults with a novel dystonic phenotype. The dystonic mice exhibit movement-induced, sustained abnormal postures of the trunk and limbs. A dominant modifier locus responsible for the difference between strains was mapped to a 4.5 +/- 1.3 cM interval on mouse chromosome 3. Our findings establish a role for ion channels in dystonia and demonstrate the impact of genetic background on its severity and progression. This new model suggests that SCN8A on chromosome 12q13 and SCNM1 on chromosome 1p21-1q21 may contribute to human inherited dystonia.

Animals↗
PubMed2000

Prevalence and inheritance of hip osteoarthritis in Iceland.

The purpose of this study was to: (I) assess the prevalence of hip osteoarthritis (OA) in Iceland and compare it with that in Southern Scandinavia, (II) determine the incidence of total hip replacement (THR) for primary OA in Iceland, (III) compare two different methods for defining radiographic hip OA, (IV) assess in a population-wide study in Iceland the genetic contribution t hip OA leading to THR, and (V) perform a genome-wide scan of a large Icelandic family to identify a chromosomal susceptibility locus for hip OA leading to THR. many Icelandic patients with hip OA have been well aware that this disease "goes in the family". by examining a large proportion of all Icelandic colon radiographs taken 1990-1996 the prevalence of radiographic hip OA in Iceland was found to be at least five-fold higher compared to Swedish and Danish studies that have used the same methods. A comparison of two methods for estimating hip OA from colon radiographs showed that a simple quantitative method of measuring joint space was more reliable than a qualitative method. The age-standardized incidence of THR for primary hip OA in Iceland between 1982 and 1996 was estimated and found to be about 50 percent higher than for Sweden. The higher Icelandic prevalence of hip OA may explain most of this difference. To investigate the contribution of heritability to hip OA leading to THR, information from two population-wide database in Iceland was combined: A national registry of THR between 1972 and 1996, and a genealogy database of all Icelandic genealogy records for the last 11 centuries made available by deCode Genetics. The genetic contribution to THR for OA was assessed by (a) identifying familial clusters of THR for OA, (b) applying the minimum founder test (MFT) to estimate the minimum number of ancestors to account for all patients with THR for OA, compared to the average number of founders for control lists, (c) calculating an average pairwise kinship coefficient (KC) for the patient and control lists, (d) estimating the relative risk (RR) for relatives of patients with THR for OA. A large number of familial clusters of patients with THR for OA were identified. MFT showed that OA patients descended from fewer founders than the control groups. The average pairwise KC among patients with OA was greater than in the population. RR for siblings of THR for OA patients was 3.05 (2.52, 3.10). Icelandic patients with THR for OA are thus significantly more related to each other than are matched controls. These findings support a significant genetic contribution to a common form of OA and encourages the search for genes conferring an increased susceptibility to OA. New techniques now make it possible to search the whole human genome for chromosomal susceptibility loci associating with OA. A genome wide scan was done to identify susceptibility loci for hip OA leading to THR, using DNA from a large Icelandic family with a very high prevalence of primary hip OA. A genome locus with a lod score of 2.58 was identified on chromosome 16p. A similar locus has been reported on from England. This is the first instance where what may be the same susceptibility locus for OA is independently described in two different populations with hip OA. We have identified other families with hip OA which link to the studied family and are continuing an expanded genome-wide scan. Continued studies of the kind outlined here will clarify the complex genetic background of OA and identify genetic variation associated with the disease. In addition to improving our understanding of the pathogenesis of OA and identifying new molecular targets for treatment, this will allow a better insight into the interactions between genetic background and environmental factors that initiate and drive OA.

Adult↗
PubMed2006

Involvement of protein kinase A in ethanol-induced locomotor activity and sensitization.

RATIONALE: Mutant mice lacking the RIIbeta subunit of protein kinase A (regulatory subunit II beta(-/-)) show increased ethanol preference. Recent evidence suggests a relationship between heightened ethanol preference and susceptibility to ethanol-induced locomotor sensitization. It is currently unknown if protein kinase A signaling modulates the stimulant effects and/or behavioral sensitization caused by ethanol administration. To address this question, we examined the effects of repeated ethanol administration on locomotor activity RIIbeta(-/-) and littermate wild-type (RIIbeta(+/+)) mice on multiple genetic backgrounds. METHODS: Over three consecutive days, mice were given single i.p. saline injections and immediately placed in a locomotor activity apparatus to establish a composite baseline for locomotor activity. Next, mice maintained on a hybrid 129/SvEvxC57BL/6J or pure C57BL/6J genetic background were given 10 i.p. ethanol injections before being placed in the activity apparatus. Each ethanol injection was separated by 3-4 days. To determine if changes in behavior were specific to ethanol injection, naïve mice were tested following repeated daily saline injections. The effects of ethanol injection on locomotor behavior were also assessed using an alternate paradigm in which mice were given repeated ethanol injections in their home cage environment. RESULTS: Relative to RIIbeta(+/+) mice, RIIbeta(-/-) mice, regardless of genetic background, consistently showed significantly greater ethanol-induced locomotor activation. RIIbeta(-/-) mice also showed increased sensitivity to ethanol-induced locomotor sensitization resulting from repeated administration, an effect that was dependent on genetic background and testing paradigm. Increased locomotor activity by RIIbeta(-/-) mice was specific to ethanol injections, and was not related to altered blood ethanol levels. CONCLUSIONS: These data provide novel evidence implicating an influence of protein kinase A signaling on ethanol-induced locomotor activity and behavioral sensitization. The observation that RIIbeta(-/-) mice are more sensitive to the effects of repeated ethanol administration suggests that normal protein kinase A signaling limits, or is protective against, the stimulant effects of ethanol and the plastic alterations that underlie behavioral sensitization.

Analysis of Variance↗
PubMed2006

Parkinson's disease and genetics.

BACKGROUND: Idiopathic Parkinson disease (IPD) is a condition of unknown cause. Several factors are believed to contribute to its onset, and many studies have been conducted in search of the possible etiology of Parkinson disease. REVIEW SUMMARY: Genetic factors have become relevant when trying to explain the onset of Parkinson disease. The studies are divided into 2 categories: epidemiological and studies that analyze twins from families with members suffering from Parkinson disease, thus looking for the responsible genetic mutations. In this article we address this controversial topic, reviewing some of the most significant studies trying to provide evidence which relates genetics to Parkinson disease. CONCLUSION: We present current epidemiological studies and the most important genetic factors related to Parkinson disease, including the latest information currently available on each issue.

Humans↗
PubMed1994

Mutagenicity testing in Salmonella typhimurium strains possessing both the His reversion and Ara forward mutation systems and different levels of classical nitroreductase or O-acetyltransferase activities.

The induction of forward mutations to L-arabinose resistance (AraR) and of reversions to histidine prototrophy (His+) can be quantitatively compared in Salmonella typhimurium BA strains. The BA bacteria carry the araD531 allele required for the Ara assay and a his auxotrophy (hisD3052 or hisG46) required for the His assay. In this study, 2 new sets of BA indicator strains have been constructed in order to combine the Ara forward and the His reverse mutation assays of S. typhimurium with deficiency, or over-production, in either classical nitroreductase or O-acetyltransferase for mutagenicity testing of nitro-containing chemicals. Nine mutagens with different chemical structures were tested to compare the specific mutagenic sensitivities of the new constructions with those of the parental and of the conventional TA indicator bacteria. The Ara test, which responded with high sensitivity to all chemicals tested, revealed important differences between the standard tester strains TA98 and TA100 with respect to the activation of mutagens considered to be dependent on classical nitroreductase activity. Total correspondence was found between the specific mutagenic sensitivities of the defective and the overproducing bacteria in the genetic background of TA98 but not in that of TA100. In the genetic background of TA100, chemicals such as nitrofurantoin and nitrofurazone displayed 10-fold reduced mutagenicity to the "classical nitroreductase" defective strain without increasing mutagenicity to the corresponding overproducing bacteria. This discrepancy might be attributed to the greater nitroreduction capability of strain TA100 (68.12 nmole/min/mg protein) as compared to TA98 (24.42 nmole/min/mg protein), by assuming that nitrofurantoin and nitrofurazone are such good substrates for classical nitroreductase that the additional enzyme activity produced from the corresponding overexpressing plasmid when present in TA100 no longer affected their metabolic activation. We propose that the Ara forward mutation test carried out in the set of over-producing bacteria constructed in the genetic background of TA98 might play a role for routine testing of large number of samples. The isogenic defective strains could be used in cases of uncertain results with the corresponding over-producing bacteria. Finally, the reversion of the his alleles accompanying the Ara assay in the BA strains could play a role in assessing the presence of mixtures of chemicals with different mutagenic specificity in samples of environmental relevance such as urban air, foods, and water.

Arabinose↗
PubMed1996

Evidence that two phenotypically distinct mouse PKD mutations, bpk and jcpk, are allelic.

Numerous mouse models of polycystic kidney disease (PKD) have been described. All of these diseases are transmitted as single recessive traits and in most, the phenotypic severity is influenced by the genetic background. However, based on their genetic map positions, none of these loci appears to be allelic and none are candidate modifier loci for any other mouse PKD mutation. Previously, we have described the mouse bpk mutation, a model that closely resembles human autosomal recessive polycystic kidney disease. We now report that the bpk mutation maps to a 1.6 CM interval on mouse Chromosome 10, and that the renal cystic disease severity in our intersubspecific intercross progeny is influenced by the genetic background. Interestingly, bpk co-localizes with jcpk, a phenotypically-distinct PKD mutation, and complementation testing indicates that the bpk and jcpk mutations are allelic. These data imply that distinct PKD phenotypes can result from different mutations within a single gene. In addition, based on its map position, the bpk locus is a candidate genetic modifier for jck, a third phenotypically-distinct PKD mutation.

Alleles↗
PubMed2002

Functional coadaptation between cytochrome c and cytochrome c oxidase within allopatric populations of a marine copepod.

Geographically isolated populations may accumulate alleles that function well on their own genetic backgrounds but poorly on the genetic backgrounds of other populations. Consequently, interpopulation hybridization may produce offspring of low fitness as a result of incompatibilities arising in allopatry. Genes participating in these epistatic incompatibility systems remain largely unknown. In fact, despite the widely recognized importance of epistatic interactions among gene products, few data directly address the functional consequences of such interactions among natural genetic variants. In the marine copepod, Tigriopus californicus, we found that the cytochrome c variants isolated from two different populations each had significantly higher activity with the cytochrome c oxidase derived from their respective source population. Three amino acid substitutions in the cytochrome c protein appear to be sufficient to confer population specificity. These results suggest that electron transport system (ETS) proteins form coadapted sets of alleles within populations and that disruption of the coadapted ETS gene complex leads to functional incompatibilities that may lower hybrid fitness.

Analysis of Variance↗
PubMed2002

[Schizophrenia and molecular genetics].

BACKGROUND: Schizophrenia is a severe mental disorder with a lifetime risk in the population of 1%. Despite extensive research, the underlying neurobiological mechanisms remain largely unknown. MATERIAL AND METHODS: Based on relevant research literature, an overview of the molecular genetics of schizophrenia is given. RESULTS AND INTERPRETATION: Family, twin and adoption studies have shown that schizophrenia has a high heritability, indicating a significant genetic component to its aetiology. There is positive linkage to chromosomal regions which probably contain susceptibility genes of moderate effect. Genetic variants in different candidate genes and different chromosome abnormalities are apparently associated with increased susceptibility to schizophrenia. However, the genetic mechanisms of schizophrenia are still largely unknown. As a result of recent advancements in molecular genetic knowledge and methods, high-throughput techniques are now available in functional genomic research that will enable genome-wide search for susceptibility genes. This has to be combined with a new clinical approach where schizophrenia is characterized based on symptoms and traits that might more directly reflect fundamental processes of relevance to the disorder.

Chromosome Mapping↗
PubMed2005

Perspective: Sign epistasis and genetic constraint on evolutionary trajectories.

Epistasis for fitness means that the selective effect of a mutation is conditional on the genetic background in which it appears. Although epistasis is widely observed in nature, our understanding of its consequences for evolution by natural selection remains incomplete. In particular, much attention focuses only on its influence on the instantaneous rate of changes in frequency of selected alleles via epistatic contribution to the additive genetic variance for fitness. Thus, in this framework epistasis only has evolutionary importance if the interacting loci are simultaneously segregating in the population. However, the selective accessibility of mutational trajectories to high fitness genotypes may depend on the genetic background in which novel mutations appear, and this effect is independent of population polymorphism at other loci. Here we explore this second influence of epistasis on evolution by natural selection. We show that it is the consequence of a particular form of epistasis, which we designate sign epistasis. Sign epistasis means that the sign of the fitness effect of a mutation is under epistatic control; thus, such a mutation is beneficial on some genetic backgrounds and deleterious on others. Recent experimental innovations in microbial systems now permit assessment of the fitness effects of individual mutations on multiple genetic backgrounds. We review this literature and identify many examples of sign epistasis, and we suggest that the implications of these results may generalize to other organisms. These theoretical and empirical considerations imply that strong genetic constraint on the selective accessibility of trajectories to high fitness genotypes may exist and suggest specific areas of investigation for future research.

Biological Evolution↗
PubMed2002

Bulimic symptoms in the Virginia Twin Study of Adolescent Behavioral Development: correlates, comorbidity, and genetics.

BACKGROUND: This paper addresses bulimia symptoms in a large community sample of twins aged 8 to 17 years. We aim to identify environmental correlates of bulimia symptoms and relationships with other psychiatric disorder symptoms. The twin design allows examination of the structure of genetic and environmental effects. METHODS: DSM-IIIR bulimia symptoms and consequential impairment were measured by interview in the first wave of the Virginia Twin Study of Adolescent Behavioral Development. Comorbidity with other psychiatric symptoms and environmental correlates were examined and the relative contributions of genes and environment were assessed using structural equation modeling. RESULTS: An item-response theory model indicated that the range of bulimic symptoms represented a single underlying trait. Bulimia symptoms were more common in postmenarche girls and positively associated with body-mass index. Subdiagnostic symptomatology was associated with impairment in psychosocial functioning. Bulimia symptoms were strongly associated with other psychiatric disorders symptoms including anxiety and depression. Genetic model fitting identified strong additive genetic effects on the symptom score. Accounting for a potential violation of the equal environment assumption for identical and fraternal twins slightly reduced estimated genetic variance. CONCLUSIONS: The pattern of comorbidity suggests overlap between bulimia symptoms and those of internalizing disorders. Substantial genetic variance (44%) was evident in the most conservative model.

Adolescent↗
PubMed2003

[Multiple sclerosis--a disease with complex genetics].

BACKGROUND: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system, characterised by demyelinisation, gliosis and various degrees of axonal damage. The cause of the disease is unknown though there is evidence that MS is an immune mediated disease in which genetic, environmental and stochastic factors are involved. MATERIAL AND METHODS: Evidence of genetic influence in MS is reviewed. RESULTS: About 20% of patients have other family members with MS. First-degree relatives of MS patients have increased risk (2-5%) of developing MS compared to the risk in the general population (0.1%). The concordance rate in monozygotic twins (25-30%) is higher than in dizygotic twins (2-5%). Genetic analysis has shown association and linkage of MS to the HLA-DR2, DQ6 haplotype. Genome-wide screens have shown chromosome regions of potential importance. CONCLUSION: MS is a complex disease in which several genes are involved. Despite extensive candidate gene studies and genome-wide linkage screens, the HLA-DR2, DQ6 haplotype is the only genetic region that has shown unequivocal association and linkage to the disease. Further studies aimed at defining other MS susceptibility and disease-modifying genes are in progress.

Genes, MHC Class II↗
PubMed2006

Chronic granulomatous disease in Latin American patients: clinical spectrum and molecular genetics.

BACKGROUND: Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by early onset of recurrent and severe infections. The molecular defects causing CGD are heterogeneous and lead to absence, low expression, or malfunctioning of one of the phagocyte NADPH oxidase components. The aim of this study was to analyze the clinical features and to investigate the molecular genetic defects of Latin American patients with CGD. PROCEDURES: The study included 14 patients. The diagnosis was based on a history of recurrent severe infections, impaired respiratory burst, and the demonstration of an underlying mutation by single strand conformation polymorphism (SSCP) or RT-PCR analysis, followed by genomic DNA or cDNA sequencing. RESULTS: Seven unrelated patients were found to have the X-linked form of CGD (X-CGD). Heterogeneous mutations affected the CYBB gene: two insertions, one substitution, and four splice site defects; two of them are novel. Seven patients presented with one of the autosomal recessive forms of CGD (A47-CGD); all had the most common mutation, a DeltaGT deletion in exon 2 of the NCF1 gene. Pneumonia was the most frequent clinical feature, followed by pyoderma, sinusitis, otitis, and liver abscess. Patients with X-CGD were more likely to have initial infections before age 2 years and to have inflammatory obstructive granulomas later. None of the patients had severe adverse reactions to BCG immunization. CONCLUSIONS: X-CGD patients from Latin America showed a high degree of molecular heterogeneity, including two novel mutations. Their clinical characteristics included early onset of infections and eventual obstructive granulomas. A47-CGD represented 50% of the reported cases, a higher prevalence than reported in other series.

DNA Mutational Analysis↗
PubMedDate not supplied

Hematopoietic malignancies associated with increased Stat5 and Bcl-x(L) expressions in Ink4a/Arf-deficient mice.

The INK4a/ARF locus, which encodes the two distinct proteins p16(INK4a) and p14(ARF), is frequently altered in various hematological malignancies as well as in other types of cancers in humans. In this study, we surveyed tumors that had spontaneously developed in Ink4a/Arf-deficient mice with an inbred FVB/NJ genetic background. We found that an Ink4a/Arf-deficiency exerted more severe effects on the induction of hematopoietic malignancies in mice with an inbred FVB/NJ genetic background than in mice with a mixed genetic background. We also provided the evidence that this prevalence of hematopoietic malignancies in Ink4a/Arf-deficient mice is associated with the upregulated expressions of Stat5 and its transcriptional target, Bcl-x(L), both of which are involved in the regulation of hematopoiesis. These results suggest a possible implication of the Ink4a/Arf locus in the control of hematopoietic pathways by negatively regulating the Stat5-signalling pathways.

Animals↗