Transcriptome project: large scale gene expression analysis using DNA-Arrays

Abstract

The Transcriptome project is included in the field of functional genomics, i.e., the meaning of the DNA sequence function at the genomic level. Although much has been known in terms of human and non-human genomic DNA or cDNA sequencing data, few studies have been conducted on the function of these genes. The wide scale gene expression evaluation is the first step on the understanding of functional genomics. The availability of mouse, human and other organism cDNA libraries, together with recent advances of robotic methodology applied to molecular biology, have permitted the development of DNA-array technology. Large number of clones, inserts and oligonucleotides are hybridized with complex probes prepared with total RNA or mRNA extracted from cells or tissues. Under adequate conditions, the quantitative signal acquisition permits the measurement of the amount of mRNA in each specimen, and therefore, the gene expression. High density of cDNA clones (micro-arrays) blotted on glass slides and hybridized with fluorochrome-labeled complex probes prepared from total RNA will be used in this project. Three complex biological conditions will be studied by means of wide range gene expression. 1) Gene expression during thymus ontogeny. Since the thymus gland is the major source for T lymphocyte maturation, and the place where the T-cell receptor V(D)J recombination occurs, the aim of this project is the evaluation of clusters of thymus genes expressed during the late phase of pregnancy, when the T-cell receptor V(D)J recombination takes place. 2) Gene expression during the acute phases of autoimmune disorders. Although several mechanisms have been implicated in the pathogenesis of autoimmune diseases, most of the pathogenic events which occur in the acute phase of these diseases have not been completely elucidated. The gene expression in lymphomononuclear cells actively involved in the pathogenesis of systemic lupus erythematosus and type I diabetes mellitus will be studied. 3) Instability of the human genome induced by in vitro irradiation. The effects of ionizing radiation at molecular level have not been completely elucidated. This study is aimed to evaluate the differential gene expression profile induced during the in vitro irradiation of normal peripheral lymphocytes and fibroplast cell lines. (AU)