BINDING OF LABELED RIBONUCLEIC ACID TO BASIC PROTEINS, A MAJOR DIFFICULTY IN RIBONUCLEIC ACID-DEOXYRIBONUCLEIC ACID HYBRIDIZATION IN FIXED CELLS IN SITU

Abstract

In an attempt to hybridize H³-ribonucleic acid (RNA) of onion roots to deoxyribonucleic acid of fixed cells in situ it has been found that such RNA binds only to cytoplasmic basic proteins (ribosomal?) as well as nuclear histones or protamines of diverse plant and animal materials. The bound RNA is relatively insensitive to mild RNase digestion. Most of these basic proteins cannot be removed from cells without distorting cell morphology, or without the prior removal of deoxyribonucleic acid. The binding characteristics of H³-RNA and basic proteins parallel alkaline fast green staining of histones. In the formalin-fixed cells, H³-RNA binds to the nucleus only after removal of deoxyribonucleic acid. The binding capacity is abolished after acetylation or deamination of lysine-rich histones; such treatments do not affect the binding ability of arginine-rich histones or protamines.