Developmental Analysis of Steady-State Levels of Cu/Zn and Mn Superoxide Dismutase mRNAs in Maize Tissues

摘要

The superoxide dismutase(Sod)steady-state mRNA levels in maize seedlings and developing kernels were examined by RNA blot analysis, using Cu/Zn and Mn cDNA probes encoding the cytosolic and mitochondrial SOD isozymes, respectively. The cytosolic (Cu/Zn)Sodsteady-state mRNA levels remained relatively constant for the various tissues examined. In contrast, the mRNA levels of the mitochondrial (Mn) SOD-3 isozyme increased in postgerminative scutella. The steady-state mRNA of theAtp2gene, F1ATPaseβsubunit, was compared to theSod3(Mn) mRNA levels. Results of this comparative study suggest that the steady-state levels of mRNAs transcribed by nuclear genes encoding essential mitochondrial proteins are independently regulated throughout development