DIFFERENTIALLY EXPRESSED MESSENGER-RNAS AS A CONSEQUENCE OF OXIDATIVESTRESS IN INTACT-CELLS

Intracellular redox conditions influence the activity of several trans cription factors leading to a modulation of the expression of the gene s controlled by these factors, We examined the changes in cell transcr iption patterns after oxidative stress induced by diethylmaleate (DEM) , Using the differential display technique me identified several diffe rentially expressed sequence tags, four of which are identical or high ly homologous to sequences contained in the human cDNAs encoding vimen tin, c-fos, cytochrome oxidase IV and ribosomal protein L4; another on e corresponds to a transcript of the mitochondrial genome of unknown f unction, The remaining five cDNAs are not recorded in any sequence dat a bank. One of these, named Rox3, lights up two mRNA species of simila r to 3400 and 3600 bp, significantly increased after treatment,vith DE M or with other oxidizing agents, This increase appears precociously a fter exposure to DEM and it is completely prevented by pretreatment wi th N-acetylcysteine. The Rox3 fragment was used to screen a cDNA libra ry; one fully sequenced clone showed 100% homology with the putative h uman guanine nucleotide regulatory protein nep1.