Evidence that deoxyribonucleic acid sequences flanking the ovalbumin gene are not transcribed

Abstract

The transcription of DNA sequences flanking the 5'' and 3'' end of the ovalbumin gene was examined. Various restriction endonuclease fragments corresponding to the 5'' and 3'' regions of the gene were isolated and used as hybridization probes to assay for the presence of transcripts corresponding to these different regions in the chick oviduct nuclear RNA. Very little, if any, of the transcripts corresponding to sequences flanking the 5'' and 3'' structural sequences of the ovalbumin gene was detected in the steady-state nuclear RNA. Pulse labeled RNA from isolated nuclei or from oviduct tissue suspension system did not hybridize significantly to DNA filters containing purified fragments of various 5''- and 3''-flanking regions again suggesting that RNA is not synthesized from the 5''- and 3''-flanking regions surrounding the gene. These results are consistent with the postulate the flanking DNA sequences are not transcribed and that the largest RNA species detected in the nuclear RNA are the initial transcripts.