02177naa a2200193 a 450000100080000000500110000800800410001910000170006024501430007726000090022052015620022965000350179165000100182670000190183670000180185570000190187370000190189277300720191114782722025-04-30       1994    bl uuuu     u00u1 u    #d1 aLOPES, M. A.  aSynthesis of an unusual α-zein protein is correlated with the phenotypic effects of the floury2 mutation in maize.h[electronic resource]  c1994  aThe soft, starchy endosperm of the maize (Zea mays L.) floury2 mutant is associated with a reduction in zein mRNA and protein synthesis, unique protein body morphology, and enhanced levels of a 70 kDa protein, that has been shown to be the maize homolog of a chaperonin found in the endoplasmic reticulum. We found as unusual x-zein protein of 24 kDa to be consistently associated with the zein fraction from floury2 mutants. Three additional x-zein proteins with molecular weights ranging from ca. 25 to 27 kDa are detected in the storage protein fraction of a high percentage of floury2 kernels and a low percentage of normal kernels in a genetically segregating population. The four proteins can be distinguished from one another by immunostaining on Western blots. Synthesis of the 24 kDa protein is regulated by Opaque2, since the 24 kDa protein is lacking in the storage protein fraction of opaque2/floury2 double mutants. The synthesis of an abnormal x-zein protein in floury2 could explain many features of the mutants, such as the abnormal protein body morphology, induction of the 70 kDa chaperonin, and hypostasis to opaque2 (o2). Although we cannot prove that the accumulation of this protein is responsible for the floury2 phenotype, we were able to detect a restriction fragment length polymorphism (RFLP) linked to the floury2 locus with a 22 kDa x-zein probe. We hypothesize that the unique characteristics of the floury2 mutant could be a response to the accumulation of a defective x-zein protein which impairs secretory protein synthesis.  aMelhoramento genético vegetal  aMilho1 aCOLEMAN, C. E.1 aKADRZYCKI, R.1 aLENDING, C. R.1 aLARKINS, B. A.  tMolecular and General Genetics, New Yorkgv. 245, p. 537-547, 1994.