EFFECTS OF ZINC-DEFICIENCY ON PEPTIDE-SYNTHESIS IN CULTURED TOBACCO PLANT-CELLS

To analyze the effects of Zn deficiency on protein synthesis at the translation and transcription levels, proteins and peptides extracted from tobacco cells cultured with (+Zn) and without Zn (-Zn) were compared by two-dimensional electrophoresis. mRNAs were compared by in vitro translation. Although the spots of translated peptides were almost identical for the -Zn and +Zn treatments, one peptide spot at pI 6.0 appeared densely by the -Zn treatment. Clear differences were observed in the separation patterns of water soluble cellular proteins and peptides. In the -Zn treatment, two peptides at pI 4.5 (MW 45,000) and at pl 5.5 (MW 50,000) which were present in the +Zn treatment disappeared while one appeared at pI 6.0 (MW 28,000). Zinc may participate in the formation of some peptides and under Zn deficiency, the transcription of one mRNA for a peptide which appeared at pI 6.0 was enhanced in this study.