Human twinning is not linked to the region of chromosome 4 syntenic with the sheep twinning gene FecB

The tendency to dizygotic (DZ) twinning is inherited in both humans and sheep, and a fecundity gene in sheep (FecB) maps to sheep chromosome 6, syntenic with human 4q21-25. Our aim was to see whether a gene predisposing to human DZ twinning mapped to this region. DNA was collected from 169 pairs and 17 sets of 3 sisters (trios) from Australia and New Zealand who had each had spontaneous DZ twins, mostly before the age of 35, and from a replication sample of 111 families (92 affected sister pairs) from The Netherlands. Exclusion mapping was carried out after typing 26 markers on chromosome 4, of which 8 spanned the region Likely to contain the human homologue of the sheep FecB gene. We used nonparametric affected sib pair methods for linkage analysis [ASPEX 2.2, Hinds and Risch, 1999]. Complete exclusion of linkage (lod < -2) of a gene conferring a relative risk for sibs as low as 1.5 ((s) > 1.5) was obtained for all but the p terminus region on chromosome 4. Exclusion in the syntenic region was stronger, down to lambda (s) = 1.3. We concluded that if there is a gene influencing DZ twinning on chromosome 4, its effect must be minor. (C) 2001 Wiley-Liss, Inc.

Stem cells in the aetiopathogenesis and therapy of rheumatic disease

Animal models of autoimmune disease and case reports of patients with these diseases who have been involved in bone marrow transplants have provided important data implicating the haemopoietic stem cell in rheumatic disease pathogenesis. Animal and human examples exist for both cure and transfer of rheumatoid arthritis, systemic lupus erythematosus (SLE) and other organ-specific diseases using allogeneic haemopoietic stem cell transplantation. This would suggest that the stem cell in these diseases is abnormal and could be cured by replacement of a normal stem cell although more in vitro data are required in this area. Given the morbidity and increased mortality in some patients with severe autoimmune diseases and the increasing safety of autologous haemopoietic stem cell transplantation (HSCT), pilot studies have been conducted using HSCT in rheumatic diseases. It is still unclear whether an autologous graft will cure these diseases but significant remissions have been obtained which have provided important data for the design of randomized trials of HSCT versus more conventional therapy. Several trials are now open to accrual under the auspices of the European Bone Marrow Transplant Group/European League Against Rheumatism (EBMT/EULAR) registry. Future clinical and laboratory research will need to document the abnormalities of the stem cell of a rheumatic patient because new therapies based on gene therapy or stem cell differentiation could be apllied to these diseases. With increasing safety of allogeneic HSCT it is not unreasonable to predict cure of some rheumatic diseases in the near future.

The progesterone receptor exon 4 Va1660Leu G/T polymorphism and risk of breast cancer in Australian women

An Alu insertion polymorphism of the progesterone receptor (PR) was reported recently to be associated with a reduced risk of breast cancer, with risks of 0.8- and 0.3-fold associated with the heterozygote and homozygote genotypes, respectively. This intronic variant is considered to be in linkage disequilibrium with an exon 4 hinge region G to T Val660Leu polymorphism. We investigated whether the exon 4 PR polymorphism was associated with breast cancer in Australian women, using a population-based study of 1452 cases and 793 controls, half of whom were

Gene-Environment Interaction Effects on Behavioral Variation and Risk of Complex Disorders: The Example of Alcoholism and Other Psychiatric Disorders

There have been few replicated examples of genotype x environment interaction effects on behavioral variation or risk of psychiatric disorder. We review some of the factors that have made detection of genotype x environment interaction effects difficult, and show how genotype x shared environment interaction (GxSE) effects are commonly confounded with genetic parameters in data from twin pairs reared together. Historic data on twin pairs reared apart can in principle be used to estimate such GxSE effects, but have rarely been used for this purpose. We illustrate this using previously published data from the Swedish Adoption Twin Study of Aging (SATSA), which suggest that GxSE effects could account for as much as 25% of the total variance in risk of becoming a regular smoker. Since few separated twin pairs will be available for study in the future, we also consider methods for modifying variance components linkage analysis to allow for environmental interactions with linked loci.

Expression analysis of delta-catenin and prostate-specific membrane antigen: Their potential as diagnostic markers for prostate cancer

The current approach to prostate cancer diagnosis has major limitations including the inability of prostate-specific antigen (PSA) assays to accurately differentiate between prostate cancer and benign prostate hyperplasia (BPH) and the imprecision of transrectal ultrasound (TRUS) biopsy sampling. We have employed cDNA microarray screening to compare gene expression patterns in BPH and tumour samples to identify expression markers that may be useful in discriminating between these conditions. Screening of 3 individual cDNA arrays identified 8 genes with expression 3-fold greater in 6 tumour tissues than in 1 nontumour sample and I BPH sample. Real-time PCR was used to confirm the overexpression of these 8 genes and 12 genes selected from the literature against a panel of 17 tumours and I 1 BPH samples. Two genes, delta-catenin (delta-catenin; CTNND2) and prostate-specific membrane antigen (PSMA; FOLH1), were significantly overexpressed in prostate cancer compared to BPH. Prostate epithelial cells stained positively for S-catenin and PSMA in our prostate cancer tissues, whereas the majority of our BPH tissues were negative for both markers. Thus we have identified delta-catenin (not previously associated with prostatic adenocarcinoma) and confirmed the potential of PSMA as potential candidates for the diagnosis and management of prostate cancer. (C) 2002 Wiley-Liss. Inc.

Linkage and Association Analysis of Radiation Damage Repair Genes XRCC3 and XRCC5 with Nevus Density in Adolescent Twins

Previous studies have shown that a deficiency in DNA damage repair is associated with increased cancer risk, and exposure to UV radiation is a major risk factor for the development of malignant melanoma. High density of common nevi (moles) is a major risk factor for cutaneous melanoma. A nevus may result from a mutation in a single UV-exposed melanocyte which failed to repair DNA damage in one or more critical genes. XRCC3 and XRCC5 may have an effect on nevus count through their function as components of DNA repair processes that may be involved directly or indirectly in the repair of DNA damage due to UV radiation. This study aims to test the hypothesis that the frequency of flat or raised moles is associated with polymorphism at or near these DNA repair genes, and that certain alleles are associated with less efficient DNA repair, and greater nevus density. Twins were recruited from schools in south eastern Queensland and were examined close to their 12th birthday. Nurses examined each individual and counted all moles on the entire body surface. A 10cM genome scan of 274 families (642 individuals) was performed and microsatellite polymorphisms in XRCC3 and adjacent to XRCC5 were also typed. Linkage and association of nevus count to these loci were tested simultaneously using a structural-equation modeling approach implemented in MX. There is weak evidence for linkage of XRCC5 to a QTL influencing raised mole count, and also weak association. There is also weak evidence for association between flat mole count and XRCC3. No tests were significant after correction for testing multiple alleles, nor were any of the tests for total association significant. If variation in XRCC3 or XRCC5 influences UV sensitivity, and indirectly affects nevus density, then the effects are small.

Genetics of melanoma predisposition

Predisposition to melanoma is genetically heterogeneous. Two high penetrance susceptibility genes, CDKN2A and CDK4, have so far been identified and mapping is ongoing to localize and identify others. With the advent of a catalogue of millions of potential DNA polymorphisms, attention is now also being focused on identification of genes that confer a more modest contribution to melanoma risk, such as those encoding proteins involved in pigmentation, DNA repair, cell growth and differentiation or detoxification of metabolites. One such pigmentation gene, MC1R, has not only been found to be a low penetrance melanoma gene but has also been shown to act as a genetic modifier of melanoma risk in individuals carrying CDKN2A mutations. Most recently, an environmental agent, ultraviolet radiation, has also been established as a modifier of melanoma risk in CDKN2A mutation carriers. Hence, melanoma is turning out to be an excellent paradigm for studying gene-gene and gene-environment interactions.

Proteasomal targeting of a viral oncogene abrogates oncogenic phenotype and enhances immunogenicity

The ability of viral or mutated cellular oncogenes to initiate neoplastic events and their poor immunogenicity have considerably undermined their potential use as immunotherapeutic tools for the treatment of human cancers. Using an EpsteinBarr virus-encoded oncogene, latent membrane protein 1 (LMP1), as a model, we report a novel strategy that both deactivates cellular signaling pathways associated with the oncogenic phenotype and reverses poor immunogenicity. We show that cotranslational ubiquitination combined with Wend rule targeting of LMP1 enhanced the intracellular degradation of LMP1 and total blockade of LMP1-mediated nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription (STAT) activation in human cells. In addition, although murine cells expressing LMP1 were uniformly tumorigenic, this oncogenicity was completely abrogated by covalent linkage of LMP1 with ubiquitin, while an enhanced CD8(+) T cell response to a model epitope fused to the C-terminus of LMP1 was observed following immunization with ubiquitinated LMP1. These observations suggest that proteasomal targeting of tumor-associated oncogenes could be exploited therapeutically by either gene therapy or vaccination.

Influence of ageing, heat shock treatment and in vivo total antioxidant status on gene-expression profile and protein synthesis in human peripheral lymphocytes

Ageing results in a progressive, intrinsic and generalised imbalance of the control of regulatory systems. A key manifestation of this complex biological process includes the attenuation of the universal stress response. Here we provide the first global assessment of the ageing process as it affects the heat shock response, utilising human peripheral lymphocytes and cDNA microarray analysis. The genomic approach employed in our preliminary study was supplemented with a proteomic approach. In addition, the current study correlates the in vivo total antioxidant status with the age-related differential gene expression as well as the translational kinetics of heat shock proteins (hsps). Most of the genes encoding stress response proteins on the 4224 element microarray used in this study were significantly elevated after heat shock treatment of lymphocytes obtained from both young and old individuals albeit to a greater extent in the young. Cell signaling and signal transduction genes as well as some oxidoreductases showed varied response. Results from translational kinetics of induction of major hsps, from 0 to 24 It recovery period were broadly consistent with the differential expression of HSC 70 and HSP 40 genes. Total antioxidant levels in plasma from old individuals were found to be significantly lower by comparison with young, in agreement with the widely acknowledged role of oxidant homeostasis in the ageing process. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Effects of leukapheresis protocol, cell processing and cryopreservation on the generation of monocyte-derived DC for immune therapy

Background Many clinical trials of DC-based immunotherapy involve administration of monocyte-derived DCs (Mo-DC) on multiple occasions. We aimed to determine the optimal cell processing procedures and timing (leukapheresis, RBC depletion and cryopreservation) for generation of Mo-DC for clinical purposes. Methods Leukapheresis was undertaken using a COBE Spectra. Two instrument settings were compared - the standard semi-automated software (Version 4.7) (n = 10) and the fully automated software (Version 6.0) (n = 40). Density gradient centrifugation using Ficoll, Percoll, a combination of these methods or neither for RBC depletion were compared. Outcomes (including cell yield and purity) were compared for cryopreserved unmanipulated monocytes and cryopreserved Mo-DC. Results Software Version 6.0 provided significantly better enrichment for monocytes (P

An investigation of the 5-HT2C receptor gene as a migraine candidate gene

Migraine is a common complex disorder, currently classified into two main subtypes, migraine with aura (MA) and migraine without aura (MO). The strong preponderance of females to males suggests an X-linked genetic component. Recent studies have identified an X chromosomal susceptibility region (Xq24-q28) in two typical migraine pedigrees. This region harbours a potential candidate gene for the disorder, the serotonin receptor 2C (5-HT2C) gene. This study involved a linkage and association approach to investigate two single nucleotide variants in the 5-HT2C gene. In addition, exonic coding regions of the 5-HT2C gene were also sequenced for mutations in X-linked migraine pedigrees. Results of this study did not detect any linkage or association, and no disease causing mutations were identified. Hence, results for this study do not support a significant role of the 5-HT2C gene in migraine predisposition. (C) 2003 Wiley-Liss, Inc.