Reference "A comparison of the structure and function of the highly homologous maize antioxidant Cu/Zn superoxide dismutase genes, Sod4 and Sod4A"

Reference ID

7637

Title

A comparison of the structure and function of the highly homologous maize antioxidant Cu/Zn superoxide dismutase genes, Sod4 and Sod4A

Source

Genetics, 1996, vol. 144, pp. 317-328

Authors (2)

Kernodle-S-P

Scandalios-J-G

Abstract

Two highly similar cytosolic Cu/Zn Sod (Sod4 and Sod4A) genes have been isolated
from maize. Sod4A contains eight exons and seven introns. The Sod4 partial
sequence contains five introns. The introns in both genes are located in the
same position and have highly homologous sequences in several regions. The
largest intron (> 1200 bp) interrupts the 5' leader sequence. The presence of
different regulatory motifs in the promoter region of each gene may indicate
distinct responses to various conditions. Zymogram and RNA blot analyses show
that Sod4 and Sod4A are expressed in all tissues of the maize plant. The
developmental profiles of Sod4 and Sod4A mRNA accumulation differ in scutella
during sporophytic development. RNA blot analysis of the respective Sod mRNAs
indicates a differential, tissue-specific response of each gene to certain
stressors. RNA isolated from stem tissue of ethephon-treated seedlings shows an
increase in the Sod4 but not the Sod4A transcript while there is no change in
transcripts of either gene in leaves or roots. There is differential mRNA
accumulation between the two genes in leaf and stem tissue of paraquat-treated
seedlings. Other agents that can cause oxidative stress were also tested for
differential expression of the genes.