THE ORGANIZATION AND EXPRESSION OF THE NATURAL OVALBUMIN GENE

Abstract: The sequence organization of the structural ovalbumin gene and flanking sequences in native chick DNA was studied by restriction mapping and filter hybridization using a nick-translated probe generated from p0V230, a recombinant plasmid which contains a full-length ovalbumin DNA synthesized from ovalbumin mRNA. The structural sequences of the ovalbumin gene in native chick DNA were found to be non-contiguous because at least two restriction endonucleases that do not cut the structural sequence do cleave the natural gene into multiple fragments by cleaving within non-structural sequences interspersed between the structural sequences. The observation that all ovalbumin DNA-containing sequences were contained within a single DNA fragment generated by Bam HI digestion of total chick DNA has allowed the construction of an inclusive restriction map of the natural ovalbumin gene which contains at least two “insert sequences”. Both “insert sequences” were located within the peptide-coding regions of the gene and the sizes of these “insert sequences” were estimated to be approximately 1.0 and 1.5 Kb, respectively. The same amazing ovalbumin gene organization is present in chick liver, oviduct and embryonic DNA. Pure single-stranded hybridization probes to each of the separate regions of the ovalbumin gene were prepared and hybridized to total chick DNA and oviduct nuclear RNA. Results indicate that transcription of the separated structural regions are coordinately regulated by estrogen.