Anaerobically regulated aldolase gene of maize. A chimaeric origin?
The sequence of the anaerobically induced fructose 1,6-bisphosphate aldolase gene of maize is presented. Analysis of the upstream sequences of the aldolase gene reveals a six base-pair sequence (TGGTTT) with perfect homology to one of the sub-regions of the anaerobic regulatory element (ARE) which is responsible for the anaerobic induction of the maize alcohol dehydrogenase 1 gene (Adh1). In the aldolase gene this sequence is located at position -70 relative to the start of transcription, in a small segment proven by functional analysis to be important for expression of the aldolase gene. Since this six base-pair sequence has been shown to be critical for anaerobic induction of the Adh1 mRNA, is in the functional promoter region of aldolase and is also present in a homologous position in Adh2 (another anaerobically-induced gene), we suggest this hexanucleotide is essential for anaerobic regulation of each of these genes. The maize aldolase gene is about 50% homologous at the amino acid level to the animal aldolase gene but has a completely different intron/exon structure. While the rat aldolase gene has nine introns the maize gene has a single large intron near the N terminus of the coding region. Because there is 55% homology downstream from the intron and very little homology upstream, we suggest that the maize gene has acquired a 5' region containing signals for anaerobic regulation and fortuitously adding a new N-terminal region to the protein. We must suppose that the plant gene has lost the remaining introns.
Dennis
E S
ES
CSIRO Division of Plant Industry, Canberra, Australia.
Gerlach
W L
WL
Walker
J C
JC
Lavin
M
M
Peacock
W J
WJ
D000693:Anaerobiosis; D001483:Base Sequence; D002678:Chimera; D004247:DNA; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011401:Promoter Regions, Genetic; D003313:Zea mays / Q000201:enzymology / Q000235:genetics
D004247:DNA; D005634:Fructose-Bisphosphate Aldolase