The inhibition of protein synthesis in meiotic cells and its effect on chromosome behavior

Abstract

Autoradiographs show that tritiated leucine is incorporated into protein continually at an almost linear rate during meiotic prophase of lily microsporocytes in in vitro culture. Although label is mostly in the cytoplasm for the first hour, it becomes almost evenly distributed throughout the cell after a few hours. The amount of label decreases slightly, if at all, during a chase period extending through the rest of the prophase — a period of 3 to 4 days. — The incorporation of label was blocked by 95% by the protein inhibitor, cycloheximide, at a concentration of 3.5 × 10^-6 M. In the presence of this inhibitor, meiosis was arrested at all stages through metaphase I and even later. After temporary inhibition, however, or in low drug concentrations, characteristic cytological abnormalities subsequently developed, depending on the meiotic stage at which the inhibition occurred. One important observation was that the formation of chiasmata between homologs could be blocked if the inhibition was applied during the late zygotene or early pachytene stages.