Function of chloroplast DNA. I. Hybridization studies involving nuclear and chloroplast DNA with RNA from cytoplasmic (80S) and chloroplast (70S) ribosomes.

Abstract

Hybridization experiments were performed with chloroplast and nuclear DNA''s and H3-RNA''s isolated from highly purified 70S chloroplast and 80S cytoplasmic ribosomes from tobacco leaves. Chloroplast DNA hybridized with chloroplast ribosomal RNA (0.5%) but not with cytoplasmic ribosomal RNA. Nuclear DNA hybridized with cytoplasmic riboscmal RNA (0.25%) and also with chloroplast ribosomal RNA (0.1%). The coding information contained in nuclei for chloroplast ribosomal RNA is about 3 times greater than that contained in chloroplast DNA on a per cell basis. The chloroplast ribosomal RNA cistrons contained in nuclear DNA occupy sites separated from the many repetitive cistrons for cyto-plasmic ribosomal RNA.