Structure of the sucrose synthase gene on chromosome 9 of Zea mays L

Abstract

The structure of the shrunken gene of Zea mays encoding sucrose synthase (EC 2.4.1.13) was determined by (i) sequencing the transcription unit and ˜1.2 kb of 5′ ‐upstream sequences from a genomic clone, (ii) by sequencing a nearly full length cDNA clone and (iii) by determining the transcription start site by a combination of primer extension experiments with synthetic oligodeoxynucleotide primers and S1 mapping. The sucrose synthase gene is 5.4 kb long, of which 2746 bp are found in the mature mRNA. The gene is interrupted by 15 introns. The first two introns are ˜1 kb and ˜0.5 kb in length, respectively, while the other introns are much smaller. A TATA box is located 30 bp upstream from the transcription start site. Approximately 610 bp upstream of the transcription start site a direct repeat of 16 nucleotides, separated by a 4‐fold repetition of the sequence GGTGG is detected. The 16‐bp sequence has similarities to a sequence repeat found between two promoters of a maize zein gene also expressed in the endosperm tissue. The transposable element Ds in the mutant sh‐m5933 and sh‐m6233 alleles is inserted in the seventh and first intron, respectively. The genomic and cDNA clones were obtained from different maize lines. This allows the determination of polymorphic sites which are frequent in 3rd codon position and absent in 1st and 2nd codon positions. In addition, the 3′ ‐untranslated sequence shows two duplications that may have arisen by the insertion and subsequent excision of transposable elements.

Post-Transcriptional Control of Sucrose Synthase Expression in Anaerobic Seedlings of Maize

“…The 5' untranslated leader sequence of ferritin mRNA confers the translational regulatory property to a heterologous gene in a transformation assay (13,14). Similarly, it may be possible to identify regions in the well-characterized Sh gene (27) that are responsible for the translational control of SS I transcripts during anaerobic stress. Another level of translational control is based on phosphorylation/dephosphorylation of a protein elongation factor 2, EF2, described in mammalian cells (21).…”

Differential expression of two types of sucrose synthase-encoding genes in wheat in response to anaerobiosis, cold shock and light

“…), which catalyzes the reversible reaction UDP + sucrose^ UDP-glucose + D-fructose, was first characterized in wheat germ by Leloir and coworkers, who also detected its activity in a great variety of plant species and tissues (Cardini et al, 1955). Recent advances on the subject have focused, to some degree, on the maize enzyme, which is a tetramer composed of subunits of 92 kDa (Su and Preiss, 1978;Chourey, 1981;Werr et al, 1985). Two non-allelic variants of the enzyme have been characterized (Chourey, 1981;Echt and Chourey, 1985) and the corresponding genes [Sh and Sus (= Ss2 = Css)] have been identified, cloned and sequenced (Chourey and Nelson, 1976;Burr and Burr, 1981;Werr et al, 1985;McCarty etal., 1986;Springer et al, 1986).…”

Linked sucrose synthase genes in group-7 chromosomes in hexaploid wheat (Triticum aestivum L.)

“…The second gene, Ss2 or Css, is also expressed in several tissues but its expression is less affected by anaerobiosis (McCarty et al, 1986a). The Shl gene has been cloned and its entire DNA sequence has been determined (Geiser et al, 1980;Sheldon et al, 1983;Werr et al, 1985;Zack et al, 1986). Based on the ability of Shl probes to select by hybridization mRNA corresponding to the Css gene (McCormick et al, 1982), Css genomic clones have been isolated and characterized by McCarty et al (1986a) who have also located the Css (Ss2) gene near the centromere of chromosome 9 of maize, 32 map units from the Shl locus (McCarty et al, 1986b).…”

“…Two genes encoding sucrose synthase (Shl and Ss2 or Css) have been described in maize (Chourey and Nelson, 1976;Chourey, 1981aChourey, , 1986McCormick et al, 1982) and the corresponding isozymes were shown to have partial antigenic identity and very similar kinetic properties in the sucrose-cleavage reaction (Echt and Chourey, 1985). Shl is the structural gene for the major endosperm form of the enzyme which is a homotetramer composed of subunits of 92 kDa (Su and Preiss, 1978;Chourey, 1981b;Werr et al, 1985). This gene is expressed in other tissues at low levéis that can be drastically increased in response to anaerobiosis (Springer et al, 1986).…”