A unique nucleoprotein structure associated with the Drosophila melanogaster 18–28 S rDNA nontranscribed spacer

Abstract

We have detected unique nucleoprotein particles specific for the 18-28 S rDNA nontranscribed spacer of Drosophila melanogaster. The particles migrate between di-and trinucleosomes on nucleoprotein gels, and are between mono-and dinucleosomal in DNA length. These migration properties suggest that the nontranscribed spacer particles could have a protein component larger than a histone core. The variant nucleoprotein structures map primarily within the nontranscribed spacer 235 base pair internal subrepeat, which is AT-rich and possesses a 50 base pair sequence homologous to the RNA polymerase I binding site. Nucleoprotein particle 18-28 S rDNA(D. melanogaster)