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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 © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Reports that interleukin-10 is a type II cytokine in the IL10 cytokine family, which contains eight cytokines located in three cytokine gene clusters in humans and mice. Identification of chicken IL10-gene cluster from a group of White Leghorns; Examination of the effects of lipopolysaccharide stimulation on IL10 gene expression; Retrieval of the amino acid sequence of chicken from the GenBank.

The article discusses comparative mapping of oculocutaneous albinism type II (OCA2), transient receptor potential cation channel, subfamily M member 1 (TRPM1) and two equine microsatellites, ASB08 and 1CA43, among four equid species by fluorescence in situ hybridization (FISH). Horse bacterial artificial chromosome clones containing genes for OCA2 and TRPM1, and linked markers, ASB08 and 1CA43, are FISH mapped to the metaphase chromosomes of the domestic horse and equid species Somali wild ass, Burchell's zebra and Hartmann's mountain zebra.

The article examines the modulation of gene expression profiles in racing horses. It takes into account the chromosomal location of interleukin 8 (IL8) in Equus caballus. A genomic DNA fragment has been amplified using primers from the horse IL8 mRNA sequence. Overlapping clones 63-D22 and 163-L3 have been isolated. Through the use of bacterial artificial chromosome clone as probe in a fluorescence in situ hybridization, the location of IL8 is determined.

We sequenced 2939 ESTs from fetal and adult sheep skin. Stages of gestation were picked to coincide with the major events in skin appendage (wool follicle) formation. Clustering analysis generated a nonredundant set of ESTs 2435 strong (83% nonredundant). Approximately 24% of these gave no hit to NCBI build 29 of the human genome, while 35% were tentatively classified by putative function based on BLASTX hits with a p(N) of <10(-4). In addition to bioinformatics analysis of our ESTs and gene mapping, we have generated a large EST spatial expression data set using in situ hybridization. One thousand one hundred forty-two ESTs have been used for in situ localization; about 31% are from adult sheep skin, 39% from late gestation fetal sheep skin, and 30% from midgestation fetal sheep skin. These probes have been used in over 3000 hybridization experiments. In this report, we summarize the results of in situs on adult sheep skin.

65,000 sheep skin cDNA clones were gridded in high density on to nylon membranes and screened for (CA)n and (GA)n repeat containing clones. 296 dinucleotide repeat-containing clones were identified with approximately 85% non-redundancy. Clones were single-pass 5' sequenced and we compared the Expressed Sequence Tag (EST) sequences to the Swiss-Prot database to ascertain their identity and/or putative function. We then aligned the ESTs against the human genomic sequence to determine the locations of human orthologous sequences. Finally, we developed a subset of polymorphic microsatellite markers and positioned them on the ovine linkage map., (Copyright 2003 S. Karger AG, Basel)

The hyaline layer of echinoderm embryos is an extraembryonic matrix that functions as a substrate for cell adhesion through early development. The major constituent of the hyaline layer is the protein hyalin, a fibrillar glycoprotein of approximately 330 kDa that multimerizes in the presence of calcium. Here we provide a molecular characterization of hyalin and identify a region of the protein that is important for its function in cell adhesion. Partial hyalin cDNAs were identified from two sea urchin species, Strongylocentrotus purpuratus and Lytechinus variegatus, by screening expression libraries with monoclonal antibodies to hyalin. The cDNAs each encode a tandemly arranged series of conserved repeats averaging 84 amino acids. These hyalin repeats are as similar between the two species as they are to repeats within each species, suggesting a strong functional conservation. Analysis of this repeat shows that it is a unique sequence within the GenBank database with only weak similarity to mucoid protein sequences. The hyalin mRNA is approximately 12 kb in length and is present in developing oocytes coincident with the appearance of cortical granules, the vesicle in which the hyalin protein is specifically packaged. The mRNA is present throughout oogenesis but is rapidly lost at oocyte maturation so that eggs and early embryos have no detectable hyalin mRNA. The hyalin protein, however, remains at relatively constant levels throughout development. Thus, all the hyalin protein present during early development, when no RNA is detectable, is maternally derived and exocytosed from cortical granules at fertilization. Hyalin mRNA reaccumulates in embryos beginning at the mesenchyme blastula stage; a RNA gel blot and in situ hybridization analysis of gastrulae and larvae shows a progressive confinement of hyalin mRNA to the aboral ectoderm. Recombinant hyalin containing the tandem repeat region of the protein was expressed in bacteria and is shown to serve as an adhesive substrate, almost equal to that of native hyalin, in cell adhesion assays. This adhesive activity is partially blocked by dilute hyalin monoclonal antibody Tg-HYL to the same extent as that for native hyalin. Thus, this hyalin repeat region appears to contain the ligand for the hyalin cell surface receptor. These data help explain some of the classic functions ascribed to the hyalin protein in early development and now enable investigators to focus on the mechanisms of cell interactions with the hyaline layer., (Copyright 1998 Academic Press.)

The extrauterine development of marsupial pouch young (northern brown bandicoot Isoodon macrourus) has facilitated the study of the effects of murine epidermal growth factor (mEGF) on pattern formation in skin. Hair follicle initiation and development, which in the mouse would occur from about Days 13-14 of gestation onward, occurs postnatally. In the present study the effect in vivo of mEGF on developing skin corresponding to mouse gestational ages from Day 13 onward was examined. Subcutaneous injections of mEGF (0.5, 1.0 and 2.0 microg g[-1] body weight) or equivalent volumes of saline (0.9% w/w) were administered daily, before and during hair follicle initiation and development. Murine EGF inhibited the formation of hair follicles, hair follicle sweat glands, sebaceous glands and dermal papillae. The pattern of follicle initiation was perturbed. The characteristic trio follicle grouping was absent, and follicle rudiment densities (no. per mm2 skin surface) were significantly lower in animals treated with mEGF, whereas follicle diameters were increased. These data may reflect a role for the epidermal growth factor (EGF) receptor in epidermal pattern formation. The EGF receptor and its potential ligands (such as EGF, transforming growth factor (TGF-alpha) or other yet-to-be-discovered ligands) perhaps act as parts of a pattern-forming system in vertebrate skin.

The distribution of metallothionein (MT) and MT mRNAs was examined in hair (wool) follicles, where high levels of cell proliferation are found and where the resulting cells provide a temporal record of differentiation events. MT was found in the cytoplasm and some nuclei of follicle bulb cells of the proliferative zone, outer root sheath cells and in basal layer cells of sebaceous glands and sweat glands. The population of 5-bromo-2'-deoxyuridine (BrdU)+ cells in these tissues overlapped, but were not completely coincident with the distribution of MT staining. MT mRNA expression in hair (wool) follicles was assessed by in situ hybridization with four gene-specific sheep MT (sMT) isoforms. Intense signals were obtained with the sMT-Ib probe in follicle bulb cells from the proliferative zone to the keratogenous zone. Signals from the sMT-Ia probe were present in the same cells, but were much weaker. No signals were detected using the sMT-Ic and sMT-II gene-specific probes. The findings suggest that: (1) MT is important in cell proliferation and/or cell differentiation in the hair follicle bulb; (2) MT translation is inhibited during cell differentiation and migration; and (3) tissue-specific expression of uncharacterized sMT isoforms is likely.

An alpha-D-galactoside-specific lectin from Bandeiraea simplicifolia (BSLI) showed differential binding to cortical cells of the wool follicle bulb. The lectin bound to cells on one side only of the bulb and was completely blocked by alpha-D-galactose. The region of lectin binding extended from presumptive cortical cells at the base of the bulb to cortical cells at the top of the bulb, disappearing as cortical cells entered the fibre cortex. An orthocortex-specific monoclonal antibody was used to show that cortical cells recognised by the lectin lie directly below the fibre orthocortex and presumably give rise to the orthocortex. The results suggest that two distinct populations of presumptive cortical cells are present only two to three cell layers from the base of the bulb in a region where no morphological differences are detectable. The lectin-bound pre-cortical cells appear to give rise to orthocortical cells while cells not bound by lectin presumably give rise to paracortical cells. Electron microscopy showed that the lectin bound to sites on the plasma membrane, probably on the extracellular surface. This suggests that the lectin target may be a membrane glycoprotein or glycolipid. Two polypeptides recognised by BSLI were separated from wool follicle extracts by SDS-gel electrophoresis. These polypeptides migrated at approximately 69 kDa and 17 kDa. However, only the 69 kDa molecule showed the expected loss of binding by BSLI in the presence of alpha-D-galactose. Further work will be required to determine if this glycoprotein is the bulb cell molecule recognised by BSLI.(ABSTRACT TRUNCATED AT 250 WORDS)

We have generated and characterized a monoclonal antibody (McA Tg-HYL) that recognizes sea urchin hyalin as evidenced by immunofluorescence staining of the hyaline layer (HL) and immunoblot staining of the hyalin protein band. On immunoblots of HL extracts only the hyalin protein reacted with McA Tg-HYL. Immunoprecipitates of radioactive proteins from embryos incubated with [35S]methionine yielded radioactive hyalin and 190, 140 and 105 x 10(3) Mr proteins associated with hyalin. McA Tg-HYL was generated against Tripneustes gratilla embryos but reacts with hyalin from the distantly related sea urchin species, Colobocentrotus atratus, Strongylocentrotus purpuratus, Arbacia punctulata, Lytechinus variegatus and Lytechinus pictus. Developing embryos of the above-mentioned six species were treated with McA Tg-HYL and did not gastrulate or form arms. Observations of treated embryos revealed areas of separation of the hyaline layer from the underlying embryonic cells, suggesting that McA Tg-HYL was interfering with binding of the cells to the HL. Using the centrifugation-based adhesion assay of McClay et al. (Proc. natn. Acad. Sci. U.S.A. 78, 4975-4979, 1981), Fab' fragments of McA Tg-HYL were found to inhibit cell-hyalin binding. McA Tg-HYL did not inhibit hyalin gelation in vitro or the reaggregation of dissociated blastula cells. We postulate that McA Tg-HYL recognizes an evolutionarily conserved hyalin domain involved in cell-hyalin binding and required for normal epithelial folding.