The application of high density microarray for analysis of mitogenic signaling and cell-cycle in the adrenal

Angiotensin II (AII) binds to specific G-protein coupled receptors and is mitogenic in adrenal, liver epithelial, and vascular smooth muscle cells. The H295R human adrenocortical cell line, which expresses AII receptors predominantly of the AT(1) subclass, proliferates in response to treatment with AII. The induction and maintenance of cellular proliferation involves a precisely coordinated induction of a variety of genes. As the human genome sequencing projects near completion a variety of high throughput technologies have been developed in order to create dynamic displays of genomic responses. One high throughput method, the gridded cDNA microarray has been developed in which immobilised DNA samples are hybridized on glass slides for the identification of global genomic responses. For this purpose high precision robotic microarrayers have been developed at AECOM. The cyclin DI gene, which encodes the regulatory subunit of the cyclin D1-dependent kinase (CD1K) required for phosphorylation of the retinoblastoma protein (pRB), was induced by An. in H295R cells. Abundance of the cyclin DI gene is rate-limiting in G(1) phase progression of the cell-cycle in a variety of cell types. AII induced cyclin D1 promoter activity through a c-Fos and c-Jun binding sequence at -954 bp. The abundance of c-Fos within this complex was increased by All treatment. Analysis of ALT signaling in adrenal cells by cDNA microarray demonstrated an induction of the human homologue of Xenopus XPMC2 (HXPMC2). The cDNA for XPMC2 was previously shown to rescue mitotic catastrophe in mutant S. Pombe defective in cdc2 kinase function. Further studies are required to determine the requirement for cyclin DI and XPMC2H in All-induced cell-cycle progression and cellular proliferation in the adrenal.