In vivo transcription of a cloned prosimian primate SINE sequence.

SINE transcription was studied by introducing a galago Monomer family member (gal39), into the mouse Ltk- cell line. Cells transiently transfected with gal39 produce gal39-specific RNA polymerase III-directed transcripts. In permanent cell lines gal39 expression was largely shut off. Genomic environment, copy number and tandem repetition of integrated SINE sequences influenced whether or not RNA polymerase III-directed gal39 transcripts were detectable. These transcripts differ in length from the observed endogenous transcript in cultured galago cells which hybridizes to this repetitive DNA family.