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 control (H-rev) were identified by differential expression cloning on the assumption that they are expressed in phenotypically normal rat cells and repressed in closely related H-ras transformed cells. Previously 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 of ril, a novel member of the heterogeneous group of genes encoding proteins with LIM/double zinc finger domains. The ril gene is expressed in normal fibroblasts and down-regulated in H-ras-transformed derivatives. Expression is restored in several independent phenotypic revertants derived from H-ras transformed cells. The predicted protein product of ril harbors a single LIM domain but lacks a homeodomain. The ril gene is highly conserved during evolution and is transcribed in various normal cell lines. Northern blot analysis and in situ hybridization studies showed that ril is expressed in meiotic spermatocytes, in somites of developing mice, and in a wide variety of tissues of adult mice.