ORCID Profile
0000-0002-4345-3013
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Publisher: Oxford University Press (OUP)
Date: 05-01-2010
DOI: 10.1189/JLB.0909624
Abstract: These studies demonstrate that CSF-1 and IL-34 are conserved in birds, and uses evolutionary comparisons to infer structure function relationships among vertebrate animals. Macrophages are involved in many aspects of development, host defense, pathology, and homeostasis. Their normal differentiation, proliferation, and survival are controlled by CSF-1 via the activation of the CSF1R. A recently discovered cytokine, IL-34, was shown to bind the same receptor in humans. Chicken is a widely used model organism in developmental biology, but the factors that control avian myelopoiesis have not been identified previously. The CSF-1, IL-34, and CSF1R genes in chicken and zebra finch were identified from respective genomic/cDNA sequence resources. Comparative analysis of the avian CSF1R loci revealed likely orthologs of mammalian macrophage-specific promoters and enhancers, and the CSF1R gene is expressed in the developing chick embryo in a pattern consistent with macrophage-specific expression. Chicken CSF-1 and IL-34 were expressed in HEK293 cells and shown to elicit macrophage growth from chicken BM cells in culture. Comparative sequence and co-evolution analysis across all vertebrates suggests that the two ligands interact with distinct regions of the CSF1R. These studies demonstrate that there are two separate ligands for a functional CSF1R across all vertebrates.
Publisher: Springer Science and Business Media LLC
Date: 06-2002
DOI: 10.1007/S00239-001-0084-Z
Abstract: Previous studies of the evolutionary history of hepatitis B virus (HBV) have been compromised by intergenotype recombination and complex patterns of nucleotide substitution, perhaps caused by differential selection pressures. We examined the phylogenetic distribution of recombination events among human HBV genotypes and found that genotypes A plus D, and genotypes B plus C, had distinct patterns of recombination suggesting differing epidemiological relationships among them. By analyzing the nonoverlapping regions of the viral genome we found strong bootstrap support for some intergenotypic groupings, with evidence of a ision between human genotypes A-E from the viruses s led from apes and human genotype F. However, the earliest events in the ergence of HBV remain uncertain. These uncertainties could not be explained by differential selection pressures, as the ratio of nonsynonymous-to-synonymous substitutions ( d(N)/ d(S)) did not vary extensively among lineages and there is no strong evidence for positive selection across the whole tree. Finally, we provide a new estimate of the mean substitution rate in HBV, 4.2 x 10(-5), which suggests that ergence of HBV in humans and apes has occurred only in the last 6000 years.
Publisher: Oxford University Press (OUP)
Date: 05-2004
Location: Spain
No related grants have been discovered for Mario Fares.