EXPRESSION OF RIL, A NOVEL LIM DOMAIN GENE, IS DOWN-REGULATED IN HRAS-TRANSFORMED CELLS AND RESTORED IN PHENOTYPIC REVERTANTS

Several candidate genes involved in the maintenance of normal growth c ontrol (H-rev) were identified by differential expression cloning on t he assumption that they are expressed in phenotypically normal rat cel ls and repressed in closely related H-ras transformed cells. Previousl y the genes coding for lysyl oxidase (H-rev142) and for an 18K-protein of unknown function (H-rev107) were recovered as cDNAs by subtraction cloning. Here we describe the identification and expression pattern o f ril, a novel member of the heterogeneous group of genes encoding pro teins with LIM/double zinc finger domains. The ril gene is expressed i n normal fibroblasts and downregulated in H-uas-transformed derivative s. Expression is restored in several independent phenotypic revertants derived from H-ras transformed cells. The predicted protein product o f ril harbors a single LIM domain but lacks a homeodomain. The ril gen e is highly conserved during evolution and is transcribed in various n ormal cell lines. Northern blot analysis and in situ hybridization stu dies showed that ril is expressed in meiotic spermatocytes, in somites of developing mice, and in a side variety of tissues of adult mice.