Structure and organization of a mammalian 5 S gene cluster

We have cloned and characterized a G+C-rich 2.2-kilobase pair Bam HI fragment which contains a single Syrian hamster 5 S rRNA gene. The cloned fragment directs the synthesis in vitro of 5 S RNA catalyzed by RNA polymerase III. Southern hybridization analysis of genomic hamster DNA indicates that the sequences present in the clone are tandemly repeated with a redundancy of 2700 copies per diploid cell.