Species- and tissue-specific transcription of complex, highly repeated satellite-like Bsp elements in the fox genome.

We have studied the transcription of highly repeated satellite-like Bsp elements containing the potential promoter boxes for RNA polymerase III in the genomes of adult silver and arctic foxes. The Bsp repeat transcripts were abundant enough to be detected by Northern blot and semiquantitative dot blot hybridizations, and the majority were found in the nuclear RNA fraction from arctic fox kidneys. Weak hybridization signals were revealed with the cytoplasmic RNA preparation from silver fox kidneys and with the nuclear RNA fraction from arctic fox liver, and their intensity was intermediate with the total RNA from arctic fox brain. Taken together, the data suggest possible genomic interspersion of some Bsp repeats in these two representatives of Canidae. The observed species-and tissue-specificity of the transcription of Bsp repeats suggests that they may potentially accomplish regulatory functions in the fox genomes.