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Brian Oliver

Publications and source records attributed to Brian Oliver.

8 recordsLinked to original sources
PubMed2003

Paucity of genes on the Drosophila X chromosome showing male-biased expression.

Sex chromosomes are primary determinants of sexual dimorphism in many organisms. These chromosomes are thought to arise via the divergence of an ancestral autosome pair and are almost certainly influenced by differing selection in males and females. Exploring how sex chromosomes differ from autosomes is highly amenable to genomic analysis. We examined global gene expression in Drosophila melanogaster and report a dramatic underrepresentation of X-chromosome genes showing high relative expression in males. Using comparative genomics, we find that these same X-chromosome genes are exceptionally poorly conserved in the mosquito Anopheles gambiae. These data indicate that the X chromosome is a disfavored location for genes selectively expressed in males.

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PubMed2002

Effect of interleukin-10 on the production of tumor necrosis factor-alpha by peripheral blood mononuclear cells from patients with chronic heart failure.

Chronic heart failure (HF) is a state of inflammatory immune activation characterized by elevated circulating levels of tumor necrosis factor-alpha (TNF-alpha). Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine that inhibits TNF-alpha production and lessens endotoxin bioactivity. It is not known whether IL-10 reduces lipopolysaccharide (LPS) stimulated TNF-alpha production of peripheral blood mononuclear cells (PBMCs) from patients with chronic HF. PBMCs were isolated from 15 patients with chronic HF (New York Heart Association functional class 3.0 +/- 0.2, left ventricular ejection fraction 30 +/- 2%, peak oxygen consumption 18.1 +/- 0.8 ml/kg/min) and 15 healthy control subjects and stimulated with 1 and 10 ng/ml LPS for 24 hours with or without prior addition of IL-10 (10 ng/ml). TNF-alpha was quantified in cell-free supernatants by an enzyme-linked immunosorbent assay. TNF-alpha, soluble TNF receptors, IL-10, and LPS were quantified in plasma. LPS stimulated TNF-alpha production was highest in those patients in New York Heart Association class II (p <0.01 vs New York Heart Association class III and IV, p <0.001 vs control subjects). IL-10 reduced PBMC TNF-alpha production in all stimulated samples at 1 and 10 ng/ml LPS (mean reduction 43% at 1 ng/ml, p <0.01 and 55% at 10 ng/ml, p <0.0001). The percentage reduction in TNF-alpha release did not differ significantly between patients and control subjects or with respect to severity of chronic HF or baseline immune parameters. Independently of clinical severity, IL-10 profoundly inhibits TNF-alpha release from PBMCs isolated from patients with chronic HF. IL-10 is, therefore, a potential therapy for use in chronic HF associated with inflammatory immune activation.

Aged↗
PubMed2002

Gene expression neighborhoods.

The finding that neighboring eukaryotic genes are often expressed in similar patterns suggests the involvement of chromatin domains in the control of genes within a genomic neighborhood.

Animals↗
PubMed2002

Functional conservation for lipid storage droplet association among Perilipin, ADRP, and TIP47 (PAT)-related proteins in mammals, Drosophila, and Dictyostelium.

Intracellular neutral lipid storage droplets are essential organelles of eukaryotic cells, yet little is known about the proteins at their surfaces or about the amino acid sequences that target proteins to these storage droplets. The mammalian proteins Perilipin, ADRP, and TIP47 share extensive amino acid sequence similarity, suggesting a common function. However, while Perilipin and ADRP localize exclusively to neutral lipid storage droplets, an association of TIP47 with intracellular lipid droplets has been controversial. We now show that GFP-tagged TIP47 co-localizes with isolated intracellular lipid droplets. We have also detected a close juxtaposition of TIP47 with the surfaces of lipid storage droplets using antibodies that specifically recognize TIP47, further indicating that TIP47 associates with intracellular lipid storage droplets. Finally, we show that related proteins from species as diverse as Drosophila and Dictyostelium can also target mammalian or Drosophila lipid droplet surfaces in vivo. Thus, sequence and/or structural elements within this evolutionarily ancient protein family are necessary and sufficient to direct association to heterologous intracellular lipid droplet surfaces, strongly indicating that they have a common function for lipid deposition and/or mobilization.

Adipose Tissue↗
PubMed2002

Genetic control of germline sexual dimorphism in Drosophila.

Females produce eggs and males produce sperm. Work in Drosophila is helping to elucidate how this sex-specific germline differentiation is genetically encoded. While important details remain somewhat controversial, it is clear that signals generated by somatic cells, probably in the embryonic gonads, are required as extrinsic factors for germline sex determination. It is equally clear that the sex chromosome karyotype of the germ cell is an intrinsic factor for germline sex determination. There is also extensive somatic signaling required for differentiation of germline cells in the adult gonads. Mismatched germline and somatic line sexual identities place germ cells in an inappropriate signaling milieu, which results in either failed maintenance of germline stems cells when female germ cells are in a male soma or overproliferation of germline cells when male germ cells are in a female soma. The well-studied somatic sex determination genes including transformer, transformer-2, and doublesex are clearly involved in the nonautonomous signaling from somatic cells, while the autonomous functions of genes including ovo, ovarian tumor, and Sex-lethal are involved in the germline. The integration of these two pathways is not yet clear.

Animals↗
PubMed2002

Sex determination signals control ovo-B transcription in Drosophila melanogaster germ cells.

Nonautonomous inductive signals from the soma and autonomous signals due to a 2X karyotype determine the sex of Drosophila melanogaster germ cells. These two signals have partially overlapping influences on downstream sex determination genes. The upstream OVO-B transcription factor is required for the viability of 2X germ cells, regardless of sexual identity, and for female germline sexual identity. The influence of inductive and autonomous signals on ovo expression has been controversial. We show that ovo-B is strongly expressed in the 2X germ cells in either a male or a female soma. This indicates that a 2X karyotype controls ovo-B expression in the absence of inductive signals from the female soma. However, we also show that female inductive signals positively regulate ovo-B transcription in the 1X germ cells that do not require ovo-B function. Genetic analysis clearly indicates that inductive signals from the soma are not required for ovo-B function in 2X germ cells. Thus, while somatic inductive signals and chromosome karyotype have overlapping regulatory influences, a 2X karyotype is a critical germline autonomous determinant of ovo-B function in the germline.

Animals↗
PubMed2002

Fly factory.

Explore the source record for details and available documents.

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