Gene dosage effects on catalase expression in maize

Abstract

Catalase levels were determined in maize scutella shortly after germination, using a series of one to three doses of the short arm of chromosome-5 (on which the gene Cat1, coding for the CAT-1 enzyme is located). Similar measurements were also done for the CAT-2 catalase using the short arm of chromosome-1 (on which the Cat2 gene coding for the CAT-2 enzyme is located). This dosage series was established using B-A translocations. Both CAT-1 and CAT-2 enzyme levels exhibit a gene dosage response. Further evidence for the response of the CAT-2 enzyme to gene-dosage was obtained by analyzing crosses involving a line (A16) in which the Cat2 gene is not expressed and a typical line (e.g. W59) having two doses of Cat2. The utility of gene-dosage in mapping structural genes and its potential significance in gene regulation in eukaryotes is discussed.