EXTENT OF DIFFERENTIATED GENE-EXPRESSION IN THE HUMAN ENDOTHELIUM-DERIVED EA HY926-CELL LINE

Vascular endothelial cells perform many differentiated functions in pr ocesses such as angiogenesis, hemostasis, and inflammation. The number of recognized differentiated functions has increased rapidly in recen t years, but there may be many more still unrecognized. The purpose of this study is to estimate the fraction of differentially expressed mR NA in a continuous human endothelium-derived cell line, EA.hy926. Rand om cDNA clones representing mRNAs from this cell line were labeled and used to probe blots of RNA from EA.hy926 cells and from cells of a re latively undifferentiated line. Of 49 random cDNAs, 5 cDNAs or 10% wer e found to represent mRNAs that are differentially expressed in EA.hy9 26 and in early passage umbilical vein endothelial cells. Since more t han 10(4) different genes are thought to be expressed in the typical m ammalian cell, our data indicate that about 10(3) gene products contri bute to the differentiated properties of endothelial cells.