RAPID PHOSPHORYLATION OF H3-HISTONE IN ISOLATED-NUCLEI OF BARLEY (HORDEUM-VULGARE L)

We studied the in vitro phosphorylation pattern of the proteins from in vivo irradiated isolated nuclei in relation to the investigations on rapid phytochrome effects on in vitro transcription of specific genes in isolated nuclei from barley (Mosinger et al., 1985, 1987). Although phosphorylation with carrier-free [gamma-P-32]ATP raises a variety of labeled proteins, the overall pattern does not show any difference due to the light pretreatment of the nuclei. Time-course analysis revealed a 17 and a 45 kDa protein as the most rapidly phosphorylated proteins. To obtain more information about the identity of both proteins we tried to determine the amino-terminal sequences of both proteins. Whereas the 45 kDa protein has a blocked amino-terminus, we identified the 17 kDa protein as H3 histone due to its sequence homology to other H3 histones from different sources.