Search

We describe the organization of a nascent international effort, the Functional Annotation of Animal Genomes (FAANG) project, whose aim is to produce comprehensive maps of functional elements in the genomes of domesticated animal species.

Being born small is associated with an increased risk of visceral obesity and insulin resistance in adult life. We have investigated the effect of IUGR on adipogenic and lipogenic gene expression in visceral fat in the lamb at 3 wk of age. Perirenal fat mass, but not adipocyte size was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24 h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females. In females, plasma nonesterified fatty acids (NEFA) concentrations during the first 24 h after birth were directly related to peroxisome proliferator-activated receptor ? (PPAR?) mRNA expression in the perirenal fat depot at 3 wk of age. In the males, in contrast to the females, PPAR? and leptin expression in perirenal visceral fat were significantly lower in IUGR compared with control lambs. Thus, the early nutritional environment programs adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and IUGR on PPAR? and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life.

Being born small is associated with an increased risk of visceral obesity and insulin resistance in adult life. We have investigated the effect of IUGR on adipogenic and lipogenic gene expression in visceral fat in the lamb at 3 wk of age. Perirenal fat mass, but not adipocyte size was greater in females than males, independent of birth weight. Plasma insulin concentrations during the first 24 h after birth predicted the size of the adipocytes and expression of adiponectin in visceral adipose tissue in both males and females. In females, plasma nonesterified fatty acids (NEFA) concentrations during the first 24 h after birth were directly related to peroxisome proliferator-activated receptor (PPAR) mRNA expression in the perirenal fat depot at 3 wk of age. In the males, in contrast to the females, PPAR and leptin expression in perirenal visceral fat were significantly lower in IUGR compared with control lambs. Thus, the early nutritional environment programs adipocyte growth and gene expression in visceral adipose tissue. The differential effect of sex and IUGR on PPAR and leptin expression in visceral fat may be important in the subsequent development of visceral obesity and the insulin resistant phenotype in later life.

Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) includes a unique glycine-alanine repeat domain that inhibits the endogenous presentation of cytotoxic T lymphocyte (CTL) epitopes through the class I pathway by blocking proteasome-dependent degradation of this antigen. This immune evasion mechanism has been implicated in the pathogenesis of EBV-associated diseases. Here, we show that cotranslational ubiquitination combined with N-end rule targeting enhances the intracellular degradation of EBNA1, thus resulting in a dramatic reduction in the half-life of the antigen. Using DNA expression vectors encoding different forms of ubiquitinated EBNA1 for in vivostudies revealed that this rapid degradation, remarkably, leads to induction of a very strong CTL response to an EBNA1-specific CTL epitope. Furthermore, this targeting also restored the endogenous processing of HLA class I-restricted CTL epitopes within EBNA1 for immune recognition by human EBV-specific CTLs. These observations provide, for the first time, evidence that the glycine-alanine repeat-mediated proteasomal block on EBNA1 can be reversed by specifically targeting this antigen for rapid degradation resulting in enhanced CD8+ T cell-mediated recognition in vitroand in vivo.

The peritrophic matrix is a prominent feature of the digestive tract of most insects, but its function, formation, and even its composition remain contentious. This matrix is a molecular sieve whose toughness and elasticity are generated by glycoproteins, proteoglycans, and chitin fibrils. We now describe a small, highly conserved protein, peritrophin-15, which is an abundant component of the larval peritrophic matrices of the Old World screwworm fly,Chrysomya bezziana,and sheep blowfly, Lucilia cuprina. Their deduced amino acid sequences code for a 8-kDa secreted protein characterized by a highly conserved and novel register of six cysteines. Two Drosophilahomologues have also been identified from unannotated genomic sequences. Recombinant peritrophin-15 binds strongly and specifically to chitin; however, the stoichiometry of binding is low (1:10,000 N-acetyl glucosamine). We propose that peritrophin-15 caps the ends of the chitin polymer. Immunogold studies localized peritrophin-15 to the peritrophic matrix and specific vesicles in cells of the cardia, the small organ of the foregut responsible for peritrophic matrix synthesis. The vesicular contents are disgorged at the base of microvilli underlying the newly formed peritrophic matrix. This is the first time that the process of synthesis and integration of a peritrophic matrix protein into the nascent peritrophic matrix has been observed.

The peritrophic membrane is a semi-permeable chitinous matrix lining the gut of most insects and is thought to have important roles in the maintenance of insect gut structure, facilitation of digestion, and protection from invasion by microrganisms and parasites. Proteins are integral components of this matrix, although the structures and functions of these proteins have not been characterized in any detail. The peritrophic membrane from the larvae of the fly Lucilia cuprina, the primary agent of cutaneous myiasis in sheep, was shown to contain six major integral peritrophic membrane proteins. Two of these proteins, a 44-kDa glycoprotein (peritrophin-44) and a 48-kDa protein (peritrophin-48) together represent >70% of the total mass of the integral peritrophic membrane proteins. Peritrophin-44 was purified and its complete amino acid sequence was determined by cloning and sequencing the DNA complementary to its mRNA. The deduced amino acid sequence codes for a protein of 356 amino acids containing an amino-terminal signal sequence followed by five similar but nonidentical domains, each of approximately 70 amino acids and characterized by a specific register of 6 cysteines. One of these domains was also present in the noncatalytic regions of chitinases from Brugia malayi, Manduca sexta, and Chelonus. Peritrophin-44 has a uniform distribution throughout the larval peritrophic membrane. Reverse transcriptase-polymerase chain reaction detected the expression of peritrophin-44 in all three larval instars but only trace levels in adult L. cuprina. The protein binds specifically to tri-N-acetyl chitotriose and reacetylated chitosan in vitro. It is concluded that the multiple cysteine-rich domains in peritrophin-44 are responsible for binding to chitin, the major constituent of peritrophic membrane. Peritrophin-44 probably has roles in the maintenance of peritrophic membrane structure and in the determination of the porosity of the peritrophic membrane. This report represents the first characterization of an insect peritrophic membrane protein.

We have previously shown that the total actin content of tumorigenic HeLa/fibroblast somatic cell hybrids is significantly lower than that of the non-tumorigenic hybrid cells. A measure of actin synthesis, relative to total protein synthesis, was obtained for these cells to determine whether the reduced actin content of the tumorigenic cells is due to specific suppression of actin synthesis. Actin synthesis was measured in cells labelled with [35S]methionine using DNase I affinity chroma-tography to isolate the actin quantitatively. The results show that actin synthesis is not specifically suppressed, since the relative amount of actin synthesized is constant for the tumorigenic and non-tumorigenic cell lines. The reduced actin content of the tumorigenic cells is therefore most likely to be the result of increased degradation of actin.

The organization of the microfilaments and the actin content of matched pairs of tumorigenic and non-tumorigenic HeLa/fibroblast hybrid cells was compared. Each pair consisted of a hybrid cell line with suppressed tumorigenicity and a segregant tumorigenic cell line derived from it. The tumorigenic HeLa parent cell line and a non-tumorigenic human fibroblast line were also included in the comparison. Microfilament organization of the cell lines was assessed by fluorescence microscopy using NBD-phallacidin, a probe that specifically binds to actin filaments. The re-expression of tumorigenicity is associated with a loss of microfilament organization. The actin content, as measured by the DNase I inhibition assay, was significantly lower in the tumorigenic hybrids and the HeLa parent than in the non-tumorigenic cells. The comparison was significant when the actin concentration was expressed either per cell or per protein. Despite this reduced level of total actin in tumorigenic cells, the ratio of monomeric to total actin remained constant in all cell lines tested.

The newly assembled Bos taurus genome sequence enables the linkage of bovine milk and lactation data with other mammalian genomes.

Background Cattle are important agriculturally and relevant as a model organism. Previously described genetic and radiation hybrid (RH) maps of the bovine genome have been used to identify genomic regions and genes affecting specific traits. Application of these maps to identify influential genetic polymorphisms will be enhanced by integration with each other and with bacterial artificial chromosome (BAC) libraries. The BAC libraries and clone maps are essential for the hybrid clone-by-clone/whole-genome shotgun sequencing approach taken by the bovine genome sequencing project.Results A bovine BAC map was constructed with HindIII restriction digest fragments of 290,797 BAC clones from animals of three different breeds. Comparative mapping of 422,522 BAC end sequences assisted with BAC map ordering and assembly. Genotypes and pedigree from two genetic maps and marker scores from three whole-genome RH panels were consolidated on a 17,254-marker composite map. Sequence similarity allowed integrating the BAC and composite maps with the bovine draft assembly (Btau3.1), establishing a comprehensive resource describing the bovine genome. Agreement between the marker and BAC maps and the draft assembly is high, although discrepancies exist. The composite and BAC maps are more similar than either is to the draft assembly.Conclusion Further refinement of the maps and greater integration into the genome assembly process may contribute to a high quality assembly. The maps provide resources to associate phenotypic variation with underlying genomic variation, and are crucial resources for understanding the biology underpinning this important ruminant species so closely associated with humans.