Kinetics of labelling of eye lens RNA's

Abstract

In the course of our investigation concerning RNA's and their role in the biosynthesis of specific lens proteins Wirmaw and Mandel, 1964 Virmaux, Mandel and Urban, 1964) we have tried to isolate the m RNA of this organ. Until now, only Scott and Bell (1965) studying chick embryo lens polysomes have reported messenger utilisation at polyribosomes level. Our study was carried out with calf lenses. Removed from the eyes within ten minutes after the death of the animals and immediatly stored in Heuvel medium (1956) at 37OC, the lenses were incubated in this medium with P 32 (100 PC/ml) for l/2, 1, 2, 4 and 6 hours. The epithelial zone RNA's were extracted by the phenol procedure of Kirby (1962) and chromatographed on methylated albumin column (Sueoka, 1962)iFig.l). The optical density curve shows three polynucleotidic peaks, a first, s RNA, then a zone containing RNA and DNA, and a last fraction of r RNA. The curve of absorbancy does not fit the curve of radioactivity which shows only two peaks, one overlapping s RNA and the second zone, and an other overlapping r RNA. The specific activities of these different peaks, computed from chromatogramms, plotted against incubation time, are recorded in fig.2. The diagram clearly shows that the RNA fraction eluted after r RNA (fract 111~) possesses a high specific activity which