Phosphoenolpyruvate carboxylase prevalent in maize roots: isolation of a cDNA clone and its use for analyses of the gene and gene expression.

In search of the gene family for phosphoenolpyruvate carboxylase (PEPC) [EC 4.1.1.31] in C4 plants, we isolated from a maize root cDNA library a new cDNA clone that cross-hybridized with a cDNA for PEPC involved in the C4 photosynthesis (Yanagisawa et al. (1988) FEBS Lett. 229, 107-110). Alignment of the nucleotide sequence with that of the probe cDNA revealed the absence of sequence homology in the 3' non-coding region between the two cDNAs. Southern blot hybridization probed with this specific sequence indicated that the corresponding gene is unique in the maize genome. Northern blot hybridization using the same probe showed that this gene-family member was expressed most strongly in roots and also in green leaves to a lesser extent, but not significantly in etiolated leaves.