Effects of zinc deficiency on peptide synthesis in cultured tobacco plant cells

Abstract

To analyze the effects of Zn deficiency on protein synthesis at the translation and transcription levels, proteins and pep tides 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 pI 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.