Loop structures in hybrids of early RNA and the separated strands of adenovirus DNA.

Abstract
Separated strands of adenovirus DNA were annealed with early cytoplasmic [human oral carcinoma KB cells] RNA and visualized by EM. DNA.cntdot.RNA duplex regions within the DNA filaments could be recognized by their heavy contour. This contour was often interrupted at distinct locations by loops of displaced, single-stranded DNA. Loops were observed and mapped in all 4 early regions of the genome. The structures appear to signal hitherto unknown mechanisms of eukaryotic gene expression.