英文摘要 |
Previous studies indicated that a 57 kDa polysome-associatedprotein (p57) accumulated in cytoplasmic polysomes when W64A maize (Zea mays L.) seedlings were inoculated with Bipolaris maydis, heat shocked, or treated with the herbicide paraquat. Efforts were made to determine the binding of this protein to ribosomes, and to study whether this protein was synthesized de novo or mobilized from another cellular structure in leaf tissues responding to stress. Pulse-labeling of inoculated seedlings with H3-leucine and treatments of seedings with the protein synthesis inhibitor, cycloheximide, indicated that p57 existed in cells before inoculation. Chloroplastic polysomes isolated from both inoculated and control leaves contained this protein. Presumably, p57 redistributed from chloroplasts to cytoplasmic polysomes and bound specifically to the 40S ribosomal subunit to inhibit translation in response to biotic and environmental stressses. |