Summary White coat colour in horses is inherited as a monogenic autosomal dominant trait showing a variable expression of coat depigmentation. Mutations in the KIT gene have previously been shown to cause white coat colour phenotypes in pigs, mice and humans. We recently also demonstrated that four independent mutations in the equine KIT gene are responsible for the dominant white coat colour phenotype in various horse breeds. We have now analysed additional horse families segregating for white coat colour phenotypes and report seven new KIT mutations in independent Thoroughbred, Icelandic Horse, German Holstein, Quarter Horse and South German Draft Horse families. In four of the seven families, only one single white horse, presumably representing the founder for each of the four respective mutations, was available for genotyping. The newly reported mutations comprise two frameshift mutations (c.1126_1129delGAAC; c.2193delG), two missense mutations (c.856G>A; c.1789G>A) and three splice site mutations (c.338-1G>C; c.2222-1G>A; c.2684+1G>A). White phenotypes in horses show a remarkable allelic heterogeneity. In fact, a higher number of alleles are molecularly characterized at the equine KIT gene than for any other known gene in livestock species.

Metastasis, the process by which cancer cells leave the primary tumour, disseminate and form secondary tumours at anatomically distant sites, is a serious clinical problem as it is disseminated disease, which is often impossible to eradicate successfully, that causes the death of most cancer patients. Metastasis results from a complex molecular cascade comprising many steps, all of which are interconnected through a series of adhesive interactions and invasive processes as well as responses to chemotactic stimuli. In spite of its clinical significance, it remains incompletely understood. This review provides an overview of some of the molecular interactions that are critical to metastasis. It summarises the principle molecular players in the major steps of the metastatic cascade. These are:(1) tumour angiogenesis,(2) disaggregation of tumour cells from the primary tumour mass, mediated by cadherins and catenins,(3) invasion of, and migration through, the basement membrane (BM) and extracellular matrix (ECM) surrounding the tumour epithelium, and subsequent invasion of the BM of the endothelium of local blood vessels. This is mediated through integrins and proteases, including urokinase form of plasminogen activator (uPA), matrix metalloproteinases (MMPs) and cathepsins,(4) intravasation of the tumour cells into the blood vessels prior to hematogeneous dissemination to distant sites,(5) adhesion of the circulating tumour cells to the endothelial cell lining at the capillary bed of the target organ site. This occurs through adhesive interactions between cancer cells and endothelial cells involving selectins, integrins and members of the immunoglobulin superfamily (IgSF),(6) invasion of the tumour cells through the endothelial cell layer and surrounding BM (extravasation) and target organ tissue and (7) the development of secondary tumour foci at the target organ site.

ABSTRACT Sheath blight is one of the most important and intractable diseases of rice (Oryza sativa) where limited control has been achieved using traditional approaches. Quantitative inheritance, extraneous traits, and environmental factors confound genetic analysis of host resistance. A method was developed to isolate and utilize a phytotoxin from Rhizoctonia solani to investigate the genetics of sheath blight susceptibility. Infiltration of the toxin preparation into plant leaves induced necrosis in rice, maize, and tomato. Using 17 rice cultivars known to vary in sheath blight resistance, genotypes were identified that were sensitive (tox-S) and insensitive (tox-I) to the toxin, and a correlation (r = 0.66) between toxin sensitivity and disease susceptibility was observed. Given the broad host range of R. solani, genotypes of host species may be both tox-S and tox-I. A total of 154 F(2) progeny from a cross between Cypress (tox-S) and Jasmine 85 (tox-I) segregated in a 9:7 ratio for tox-S/tox-I, indicating an epistatic interaction between two genes controls sensitivity to the toxin in rice. This work provides the means to genetically map toxin sensitivity genes and eliminate susceptible genotypes when developing sheath blight-resistant rice cultivars.

The appaloosa coat spotting pattern in horses is caused by a single incomplete dominant gene (LP). Homozygosity for LP (LP/LP) is directly associated with congenital stationary night blindness (CSNB) in Appaloosa horses. LP maps to a 6cM region on ECA1. We investigated the relative expression of two functional candidate genes located in this LP candidate region (TRPM1 and OCA2), as well as three other linked loci (TJP1, MTMR10, OTUD7A) by quantitative real-time RT-PCR. No large differences were found for expression levels of TJP1, MTMR10, OTUD7A and OCA2. However, TRPM1 (Transient Receptor Potential Cation Channel, Subfamily M, Member 1) expression in the retina of homozygous appaloosa horses was 0.5% the level found in non-appaloosa horses (R= 0.0005). This constitutes a greater than 1800 fold change (FC) decrease in TRPM1 gene expression in the retina (FC =-1870.637; P = 0.001) of CSNB affected (LP/LP) horses. TRPM1 was also down-regulated in LP/LP pigmented skin (R = 0.005, FC =-193.963, P = 0.001), in LP/LP unpigmented skin (R = 0.003, FC=- 288.686, P=0.001) and down-regulated to a lesser extent in LP/lp unpigmented skin (R = 0.027, FC =-36.583 P = 0.001). TRP proteins are thought to have a role in controlling intracellular Ca(2+) concentration. Decreased expression of TRPM1 in the eye and the skin may alter bipolar cell signaling as well as melanocyte function; thus causing both CSNB and LP in horses.

The tobiano white-spotting pattern is one of several known depigmentation phenotypes in horses and is desired by many horse breeders and owners. The tobiano spotting phenotype is inherited as an autosomal dominant trait. Horses that are heterozygous or homozygous for the tobiano allele (To) are phenotypically indistinguishable. A SNP associated with To had previously been identified in intron 13 of the equine KIT gene and was used for an indirect gene test. The test was useful in several horse breeds. However, genotyping this sequence variant in the Lewitzer horse breed revealed that 14% of horses with the tobiano pattern did not show the polymorphism in intron 13 and consequently the test was not useful to identify putative homozygotes for To within this breed. Speculations were raised that an independent mutation might cause the tobiano spotting pattern in this breed. Recently, the putative causative mutation for To was described as a large chromosomal inversion on equine chromosome 3. One of the inversion breakpoints is approximately 70 kb downstream of the KIT gene and probably disrupts a regulatory element of the KIT gene. We obtained genotypes for the intron 13 SNP and the chromosomal inversion for 204 tobiano spotted horses and 24 control animals of several breeds. The genotyping data confirmed that the chromosomal inversion was perfectly associated with the To allele in all investigated horses. Therefore, the new test is suitable to discriminate heterozygous To/+ and homozygous To/To horses in the investigated breeds.

Dendritic cells provide a critical link between innate and adaptive immunity and are essential to prime a naive T-cell response. The transition from immature dendritic cells to mature dendritic cells involves numerous changes in gene expression; however, the role of post-transcriptional changes in this process has been largely ignored. Tristetraprolin is an AU-rich element mRNA-binding protein that has been shown to regulate the stability of a number of cytokines and chemokines of mRNAs. Using TTP immunoprecipitations and Affymetrix GeneChips, we identified 393 messages as putative TTP mRNA targets in human dendritic cells. Gene ontology analysis revealed that approximately 25% of the identified mRNAs are associated with protein synthesis. We also identified six MHC Class I alleles, five MHC Class II alleles, seven chemokine and chemokine receptor genes, indoleamine 2,3 dioxygenase, and CD86 as putative TTP ligands. Real-time PCR was used to validate the GeneChip data for 15 putative target genes and functional studies performed for six target genes. These data establish that TTP regulates the expression of DUSP1, IDO, SOD2, CD86, and MHC Class I-B and F via the 3'-untranslated region of each gene. A novel finding is the demonstration that TTP can interact with and regulate the expression of non-AU-rich element-containing messages. The data implicate TTP as having a broader role in regulating and limiting the immune response than previously suspected.

PURPOSE We show the result of a randomized phase II clinical trial with an epidermal growth factor (EGF)-based cancer vaccine in advanced non-small-cell lung cancer (NSCLC) patients, evaluating immunogenicity, safety, and effect on survival. PATIENTS AND METHODS Eighty patients with stage IIIB/IV NSCLC after finishing first-line chemotherapy were randomly assigned to receive best supportive care or EGF vaccinations. Results Vaccination was safe. Adverse events were observed in less than 25% of cases and were grade 1 or 2 according to National Cancer Institute Common Toxicity Criteria. Good anti-EGF antibody response (GAR) was obtained in 51.3% of vaccinated patients and in none of the control group. Serum EGF concentration showed a major decrease in 64.3% of vaccinated patients. GAR patients survived significantly more than those with poor antibody response (PAR). Also, patients whose serum EGF dropped below 168 pg/mL survived significantly more than the rest. There was a trend to an increased survival for vaccinated patients compared with controls. The survival advantage for vaccinated patients compared with controls was statistically significant in the subgroup of patients with age younger than 60 years. CONCLUSION Vaccination with EGF was safe and provoked an increase in anti-EGF antibody titers and a decrease in serum EGF. There was a direct correlation between antibody response and survival. There was a direct correlation between decrease in serum EGF and survival. In patients younger than 60 years, vaccination was associated with increased survival.

Tobiano is a white spotting pattern in horses caused by a dominant gene, Tobiano(TO). Here, we report TO associated with a large paracentric chromosome inversion on horse chromosome 3. DNA sequences flanking the inversion were identified and a PCR test was developed to detect the inversion. The inversion was only found in horses with the tobiano pattern, including horses with diverse genetic backgrounds, which indicated a common genetic origin thousands of years ago. The inversion does not interrupt any annotated genes, but begins approximately 100 kb downstream of the KIT gene. This inversion may disrupt regulatory sequences for the KIT gene and cause the white spotting pattern. This manuscript is accompanied by supplemental figures S1, S2 and S3, as well as supplemental Tables S1 and S2 (www.karger.com/doi/10.1159/000112065). The DNA sequence generated in this work has been submitted to GenBank under the following accession number: EF442014. Copyright (c) 2007 S. Karger AG, Basel.

It is becoming increasingly apparent that cell surface oligosaccharides play pivotal roles as recognition molecules in a range of cell communication and adhesion processes. Alterations in cellular glycosylation are also associated with diseases, including cancer, and may have functional significance. This paper gives an overview of the complex topic of cellular glycosylation mechanisms and reviews the well-documented alterations in cellular glycosylation of proteins in malignancy. One particular type of cancer-associated glycosylation change, the incomplete synthesis of O-linked glycans, is highlighted, and its possible functional significance in cancer cell metastatic mechanisms is discussed. The significance that cancer-associated changes in glycoprotein glycosylation may have in new approaches to anti-tumour therapies is explored.

TNF-alpha production is regulated by transcriptional and post-transcriptional mechanism. LPS activates the NFkappaB pathway increasing TNF-alpha transcription. LPS also activates the MAP Kinase pathways resulting in stabilization and enhanced translation of the TNF-alpha message. In addition, nuclear export of the TNF-alpha mRNA is a regulated posttranscriptional process involving the Tpl2-ERK pathway and requiring the presence of the TNF- AU-Rich Element (ARE). We demonstrate that nuclear export of the TNF-alpha message requires not only the TNF-alpha AU-Rich Element but also the interaction of the proteins TAP and NxT1, both of which are involved in nucleo-cytoplasmic transport of mRNA. Through the use of dominant negative ERK1 and ERK2, we establish that control of TNF-alpha mRNA nuclear export operates specifically through ERK1. Finally, we examined the role of two established TNF-alpha ARE binding proteins, HuR and TTP, that shuttle between the nucleus and cytoplasm. These data demonstrate that neither TTP nor HuR is required for TNF-alpha mRNA export. It is unclear at this time if ARE binding protein(s) directly interact with the TAP/NxT1 complex or if each complex is independently targeted by ERK1.