C-reactive protein induces signaling through Fc gamma RIIa on HL-60 granulocytes.

Human C-reactive protein (CRP) at acute phase levels of 10-200 microg/ml triggered the phosphorylation of FcgammaRIIa, Syk kinase, and phospholipase Cgamma2 in granulocytic HL-60 cells. CRP also stimulated translocation to the membrane of both phospholipase Cgamma2 and phosphatidylinositol-3-kinase. The signaling response triggered by CRP was a rapid, early event with kinetics similar to the response elicited by human IgG. Both soluble-aggregated CRP and monomeric CRP cross-linked FcgammaRII to generate a signal of the same intensity. The results are consistent with signaling through the intrinsic immunoreceptor tyrosine-based activation motif of the cytoplasmic domain of FcgammaRIIa, the major CRP-receptor on monocytes and neutrophils that is responsible for CRP-mediated phagocytosis. The signaling events driven by CRP have the potential to regulate infiltrating neutrophil activities.

Large-scale copy number polymorphism in the human genome.

The extent to which large duplications and deletions contribute to human genetic variation and diversity is unknown. Here, we show that large-scale copy number polymorphisms (CNPs) (about 100 kilobases and greater) contribute substantially to genomic variation between normal humans. Representational oligonucleotide microarray analysis of 20 individuals revealed a total of 221 copy number differences representing 76 unique CNPs. On average, individuals differed by 11 CNPs, and the average length of a CNP interval was 465 kilobases. We observed copy number variation of 70 different genes within CNP intervals, including genes involved in neurological function, regulation of cell growth, regulation of metabolism, and several genes known to be associated with disease.

Representational oligonucleotide microarray analysis: a high-resolution method to detect genome copy number variation.

We have developed a methodology we call ROMA (representational oligonucleotide microarray analysis), for the detection of the genomic aberrations in cancer and normal humans. By arraying oligonucleotide probes designed from the human genome sequence, and hybridizing with "representations" from cancer and normal cells, we detect regions of the genome with altered "copy number." We achieve an average resolution of 30 kb throughout the genome, and resolutions as high as a probe every 15 kb are practical. We illustrate the characteristics of probes on the array and accuracy of measurements obtained using ROMA. Using this methodology, we identify variation between cancer and normal genomes, as well as between normal human genomes. In cancer genomes, we readily detect amplifications and large and small homozygous and hemizygous deletions. Between normal human genomes, we frequently detect large (100 kb to 1 Mb) deletions or duplications. Many of these changes encompass known genes. ROMA will assist in the discovery of genes and markers important in cancer, and the discovery of loci that may be important in inherited predispositions to disease.