A transcribed satellite DNA from the bullfrog Rana catesbeiana

We have cloned and sequenced a 360 bp repeated sequence from genomic DNA of the bullfrog Rana catesbeiana. This sequence, which we call satellite 1, makes up 0.7% of the genome (1.6 X 10(5) repeats) and is scattered throughout the length of all the chromosomes. In situ hybridization with strand-specific probes demonstrated that transcripts from both strands of satellite 1 occur on lamp-brush chromosome loops. We suggest that these transcripts arise by readthrough from upstream structural gene promoters. Sequences that cross-react with satellite 1 were found in genomic DNA of four out of five other Rana species that we tested, but were absent from the DNA of Xenopus, Bombina, and Acris.