玉米胚发育过程中热激蛋白的合成

35S-Met标记玉米胚蛋白合成结果表明,热激处理(42℃)与对照(25℃)的蛋白合成趋势相近,热激抑制16 DAP的蛋白合成,增加22和34 DAP蛋白合成.SDS-PAGE自显影图谱表明,热激诱导16DAP的胚合成86.4、80.0、73.2 kD等3种分子量较高的热激蛋白,22DAP后热激诱导合成86.4、80.0、73.2、24.4、18.2、16.8和13.6 kD等7种分子量的热激蛋白.2D-PAGE自显影图谱进一步显示,热激诱导22和28 DAP的胚合成近20种热激蛋白,其中超过10种为小分子热激蛋白.特异热激蛋白BiP(HsP70)、PDI(HsP60)Western blot表明,这2种热激蛋白在玉米胚发育过程均有高水平的表达,热激对其合成影响不明显.

Synthesis of Heat Shock Proteins in Developing Maize Embryo

Labeling of protein in developing maize embryo with (35)S-Met showed that, the protein synthesis rate in heat shock (42 degrees C) was similar to that in the control (25 degrees C). Heat shock inhibited protein synthesis at 16 DAP, whereas it stimulated protein synthesis at 22 and 34 DAP. The pattern of SDS-PAGE showed that, a new set of heat shock proteins were induced after heat shock. At 16 DAP, heat shock induced 3 kinds of HSPs with molecular weight 86.4, 80.0 and 73.2 kD. And at 22 DAP, 7 kinds HSPs were induced with molecular weight 86.4, 80.0, 73.2, 24.4, 18.2, 16.8 and 13.6 kD. After 22 DAP, except 3 kinds of protein with molecular weight 73.2, 24.4 and 18.2 kD were induced turnover synthesis, other 4 kinds were increased by heat shock. The pattern of 2D-PAGE further suggested that, heat shock induced more than 20 kinds of HSPs at 22 and 28 DAP, especially the smHSP of 20-30 kD were more than 10 kinds. Western blot indicated that, BiP (HSP70) and PDI (HSP60) kept a high expression level during the embryo development, and failed to respond to heat shock.