THE PLANT CELL, Vol 1, Issue 3 275-284, Copyright © 1989 by American Society of Plant Biologists
Regulation of the Aspergillus nidulans Pectate Lyase Gene (pelA)
R. A. Dean and W. E. Timberlake
Department of Plant Pathology, University of Georgia, Athens, Georgia 30602
Aspergillus nidulans pectate lyase was purified from culture filtrates. The
enzyme catalyzed a random eliminative cleavage reaction, had an apparent
molecular weight of 40,000, and a pl of 4.2. Pectate lyase antisera were
produced and used to identify pectate lyase clones in a cDNA expression
library. Thirteen of 14 clones identified immunologically cross-hybridized.
The identity of the single-copy pectate lyase gene, which we designated
pelA, was confirmed in two ways. First, several cDNA clones expressed
pectate lyase activity in Escherichia coli. Second, targeted mutation of
the gene in A. nidulans resulted in complete loss of enzyme activity. pelA
encodes a 1,300-nucleotide mRNA that was present in cells grown with
polygalacturonic acid as carbon source but absent from cells grown with
glucose or acetate as carbon source. Thus, pectate lyase expression is
regulated at the level of mRNA accumulation.
