Temporal and tissue-specific expression of mouse ets genes.

The expression of ets genes has been studied in mouse tissues and regenerating murine liver, an in vivo model for cell proliferation. Our results indicate that the ets-1 and ets-2 loci are transcriptionally active; the ets-2 locus encodes a major mRNA (3.5 kilobases) and is expressed in most of the tissues examined, whereas the ets-1 locus encodes a major 5.3-kilobase and minor 4.0-, 2.5-, and 2.2-kilobase RNA species and is expressed at a high level in thymus; both ets-1 and ets-2 mRNA are abundant in young proliferating tissues and are greatly reduced in terminally differentiated tissues, except thymus; compensatory growth of liver induces ets-2 mRNA before DNA synthesis, but after fos and myc induction; and ets-2 mRNA, but not ets-1 mRNA, is stabilized in the presence of cycloheximide during hepatic regeneration. These results suggest that ets-2 gene expression is intrinsically linked with cell proliferation. Thus, ets-2 expression follows a pattern similar to other members of the nuclear oncogene family. During hepatic regeneration, the ets-1 and ets-2 loci are subject to differential regulation.