ENDOTHELIAL-CELL EXPRESSION OF TESTICAN MESSENGER-RNA

By screening random cDNAs from a continuous vascular endothelial cell line, EA.hy926, we identified a 5 kb mRNA that is expressed at high le vels by this human cell line and by an early passage umbilical vein en dothelial cell line. It is detected at lower levels in certain stromal cell lines, but it is not detected in most other cell lines tested, i ndicating that it represents a differentially expressed function rathe r than a ubiquitous or housekeeping function. This mRNA was readily de tected in samples derived from most human organs as might be expected for a gene expressed in the vascular wall. Sequencing of the 5 kb mRNA reveals its identity with 3.5 kb of previously published testis-deriv ed cDNA sequence called testican (Alliel et al., 1993). Differential e xpression of this gene by endothelial cells contributes a new perspect ive on the potential function of testican.