FUNCTIONAL QUANTITATIVE-ANALYSIS OF THE GENOME IN CULTURED HUMAN MESANGIAL CELLS - TECHNICAL NOTE

For normal physiological function, each cell tightly regulates gene ex pression in a specific fashion so that critical proteins are synthesiz ed in a well-coordinated manner. Therefore, it is very important to un cover which genes are expressed in specific cells. Recent technologica l advances combined with rapid large-scale DNA sequencing and computer ized data processing have allowed us to investigate the expression lev els of a variety of transcripts in the mesangial cells, a target of in jury in many forms of glomerulonephritis. Utilizing a large scale sequ encing of a 3'-directed cDNA library, which allows us to avoid variabl e cloning efficiencies reflecting the size of cDNA, we investigated ex pression profiles of various molecules in cultured human mesangial cel ls. Among the 1,193 sequenced clones, 688 (57.7%) appeared more than o nce (redundant sequence group), representing 203 different species. Th irty-nine of these appeared more than three times. The most abundant m RNA was that of fibronectin, which consisted of 3.9% of the total mRNA population. Except for mitochondrial or ribosomal genes, calcyclin ca me next (2.5%), followed by two cytoskeletal genes, gamma-actin gene a nd calpactin 1 light chain gene, in addition to an amyloid precursor p rotein homolog (0.7%). In conclusion, we performed a molecular biologi cal quantification of transcripts in mesangial cells. Fibronectin was the most abundantly expressed, followed by calcyclin, gamma-actin, cal pactin 1 light chain, and an amyloid precursor protein homolog. We als o discovered some candidate genes specific for human mesangial cells. The expression profile of the transcripts serves as an important tool in understanding the biological properties of mesangial cells.