Isolation by PCR of a cDNA clone from pea petals with similarity to petunia and wheat zinc finger proteins

The C2H2 TFIIIA/Krüppel class of zinc finger proteins are an important group of regulatory nucleic acid binding factors and have been extensively studied in humans, Drosophila and yeast. We have employed 3' RACE PCR, using a highly degenerate oligonucleotide primer, for the facile isolation of a C2H2 zinc finger protein cDNA (Pszfl) from pea petals. The Pszfl cDNA open reading frame potentially encodes a protein with two widely separated zinc fingers similar to zinc finger proteins from petunia and wheat. This class of two-fingered zinc finger proteins, possessing a wide and variable linker sequence, appears to be unique to plants. Three regions outside the zinc finger domains are also conserved between the members of the plant zinc finger protein family and one of these regions is a candidate nuclear localisation signal. The Pszfl amino acid sequence is most similar to that of the petunia Epfl protein, they possess an interfinger linker sequence of approximately the same length and they have a similar expression pattern with maximal transcript accumulation in mature petals, suggesting that Pszfl may be the pea homologue of the petunia Epfl zinc finger gene.