@article{guan_scandalios_2002, title={Catalase gene expression in response to auxin-mediated developmental signals}, volume={114}, ISSN={["1399-3054"]}, DOI={10.1034/j.1399-3054.2002.1140215.x}, abstractNote={The effect of auxin on maize catalase gene expression was examined at several different developmental stages during embryo and seedling development. All three catalase genes and their respective proteins were induced by both natural and synthetic auxin in immature embryos. Total catalase (CAT) activity increased dramatically in response to high concentrations of auxin, with CAT‐2, which is not normally expressed at this stage, being the isozyme most responsible for the increase. Cat1 transcript accumulated to high levels at 2–8 h after auxin treatment, while Cat2 and Cat3 transcripts increased dramatically, but only after 12 h. In CAT‐2 null mutant lines, the CAT‐1 isozyme compensated for the missing CAT‐2 activity and was the major isozyme responsible for the observed increase in total CAT activity. Auxin treatment mimics the germination process (i.e. induces germination) in immature embryos. Thus, the observed early induction of CAT‐1 and the later increase of CAT‐2 during the germination process may be due, in part, to changes in auxin content. In germinating embryos, auxin also induces total CAT activity and Cat transcript accumulation, although to a lesser extent. Auxin also induces Cat1 transcript accumulation in young leaves. The involvement of ROS in the auxin response is discussed.}, number={2}, journal={PHYSIOLOGIA PLANTARUM}, author={Guan, LQM and Scandalios, JG}, year={2002}, month={Feb}, pages={288–295} }
 @article{guan_scandalios_1998, title={Effects of the plant growth regulator abscisic acid and high osmoticum on the developmental expression of the maize catalase genes}, volume={104}, ISSN={["1399-3054"]}, DOI={10.1034/j.1399-3054.1998.1040317.x}, abstractNote={The effects of abscisic acid (ABA) and high osmoticum on catalase (Cat) gene expression in maize have been examined. Each Cat gene responds differently to ABA and osmotic stress at different developmental stages and in different tissues. Cat1 transcript accumulates to high levels in developing and germinating embryos, and in leaves. In embryos, Cat2 and Cat3 transcripts are up‐regulated only at very high ABA concentrations during late embryogenesis and in response to various concentrations of ABA in germinating embryos. Cat3 transcript is down‐regulated by ABA and osmotic stress in leaves. Accumulation of Cat1 transcript in response to osmotic stress is a consequence of increased endogenous ABA levels. Our data suggest that two separate pathways might be involved in the ABA‐mediated induction of Cat1. The Vp1 trans‐acting factor is required for maximum induction of Cat1 transcript in wild‐type (Vp1/—) and in W64A developing embryos; however, Vp1 is not required for inducing the Cat1 transcript in vp1 mutant developing embryos, nor in W64A germinating embryos or in leaves. Given the fact that the Cat genes have a known function, we hypothesize that the increase in Cat gene products in response to ABA is due, in part, to ABA‐mediated metabolic changes leading to changes in oxygen free radical levels, which in turn, lead to the induction of the antioxidant defense system.}, number={3}, journal={PHYSIOLOGIA PLANTARUM}, author={Guan, LQ and Scandalios, JG}, year={1998}, month={Nov}, pages={413–422} }
 @article{guan_scandalios_1998, title={Two structurally similar maize cytosolic superoxide dismutase genes, Sod4 and Sod4A, respond differentially to abscisic acid and high osmoticum}, volume={117}, ISSN={["1532-2548"]}, DOI={10.1104/pp.117.1.217}, abstractNote={Abstract}, number={1}, journal={PLANT PHYSIOLOGY}, author={Guan, LQ and Scandalios, JG}, year={1998}, month={May}, pages={217–224} }
 @article{guan_polidoros_scandalios_1996, title={Isolation, characterization and expression of the maize Cat2 catalase gene}, volume={30}, ISSN={["1573-5028"]}, DOI={10.1007/BF00020803}, abstractNote={The maize Cat2 gene was isolated by direct cloning and PCR. The clones were mapped and sequenced. The start site of transcription was determined by primer extension. Computer analysis of the 1.6 kb Cat2 promoter sequence has revealed an obvious TATA box, tow GC boxes, a putative GA response element, and several ACGT core sequences known to have diverse regulatory functions in plants. Several other protein binding motifs were also identified within 800 bp upstream from the transcriptional start site. Five introns were identified in the Cat2 coding region. All five Cat2 introns are located in exactly the same position as five of the six introns in Cat1. Two of the Cat2 introns are located in the same position as the two Cat3 introns. The identical positioning of these introns suggests an evolutionary link between all three maize catalase genes. The response of the CAt2 gene to plant growth regulators was examined. Results clearly showed that the response of CAt2 to several environmental factors are developmental stage-dependent. Thus, complex regulatory mechanisms appear to be involved in the regulation of Cat2 expression in maize.}, number={5}, journal={PLANT MOLECULAR BIOLOGY}, author={Guan, LQ and Polidoros, AN and Scandalios, JG}, year={1996}, month={Mar}, pages={913–924} }
 @article{guan_scandalios_1996, title={Molecular evolution of maize catalases and their relationship to other eukaryotic and prokaryotic catalases}, volume={42}, ISSN={["1432-1432"]}, DOI={10.1007/BF02352287}, abstractNote={We have compared the nucleotide and protein sequences of the three maize catalase genes with other plant catalases to reconstruct the evolutionary relationship among these catalases. These sequences were also compared with other eukaryotic and prokaryotic catalases. Phylogenies based on distances and parsimony analysis show that all plant catalases derive from a common ancestral catalase gene and can be divided into three distinct groups. The first, and major, group includes maize Cat1, barley Cat1, rice CatB, and most of the dicot catalases. The second group is an apparent dicot-specific catalase group encompassing the tobacco Cat2 and tomato Cat. The third is a monocot-specific catalase class including the maize Cat3, barley Cat2, and rice CatA. The maize Cat2 gene is loosely related to the first group. The distinctive features of monocot-specific catalases are their extreme high codon bias at the third position and low degree of sequence similarity to other plant catalases. Similarities in the intron positions for several plant catalase genes support the conclusion of derivation from a common ancestral gene. The similar intron position between bean catalases and human catalase implies that the animal and plant catalases might have derived from a common progenitor gene sequence.}, number={5}, journal={JOURNAL OF MOLECULAR EVOLUTION}, author={Guan, LQ and Scandalios, JG}, year={1996}, month={May}, pages={570–579} }
 @article{guan_scandalios_1993, title={Characterization of the catalase antioxidant defense gene Cat1 of maize, and its developmentally regulated expression in transgenic tobacco}, volume={3}, DOI={10.1046/j.1365-313X.1993.03040527.x}, abstractNote={A genomic clone containing the maize Cat1 gene has been isolated and its complete DNA sequence determined. The start of transcription has been mapped by primer extension. Six introns were identified in the Cat1 coding region. In order to determine the tissue‐specific expression pattern of the Cat1 gene, promoter‐reporter gene fusion constructs were made consisting of 2.5 kb and 0.8 kb of the 5′Cat1 sequence fused to the coding region of the β‐glucuronidase (GUS) gene. These fusion constructs were introduced into Nicotiana tabacum cv. Burley 21 and the expression of Cat1—GUS in various tissues was examined. In transgenic tobacco, the Cat1 promoter can drive GUS activity starts to accumulate at about 10 days after flowering, reaching a maximum at about 22 days after flowering, and decreases thereafter, but persists until after seed desiccation through early germination. Low levels of GUS activity can be detected in pollen. This corresponds to the Cat1 expression pattern observed in maize.}, number={4}, journal={Plant Journal}, author={Guan, L. Q. and Scandalios, J. G.}, year={1993}, pages={527} }
 @article{guan_ruzsa_skadsen_scandalios_1991, title={COMPARISON OF THE CAT2 COMPLEMENTARY-DNA SEQUENCES OF A NORMAL CATALASE ACTIVITY LINE (W64A) AND A HIGH CATALASE ACTIVITY LINE (R6-67) OF MAIZE}, volume={96}, ISSN={["1532-2548"]}, DOI={10.1104/pp.96.4.1379}, abstractNote={CAT' (H202:H202 oxidoreductase, EC 1.1 1.1.6) is a tetrameric heme-containing enzyme found in all aerobic organisms. It can protect aerobic organisms from the toxic effects of hydrogen peroxide and other active oxygen species by converting hydrogen peroxide into water and molecular oxygen (3). In maize (Zea mays L.), three unlinked structural genes, Cat], Cat2, and Cat3 encode three isozymes CAT1, CAT-2, and CAT-3 that are differentially expressed temporally, spatially, and in response to environmental signals in the developing seedling (5). We have cloned and sequenced the Cat2 cDNA from maize inbred line W64A (the typical catalase activity line). Polyadenylated RNA was isolated from 2-d-old W64A scutella. A cDNA library was constructed in the X-Zap vector with the double-stranded cDNA synthesized by the method of Gubler and Hoffman (2). The library was plated on Escherichia coli BB4 and screened with the Cat2 gene-specific probe (4). The positive clone was further subcloned into Bluescript vector and sequenced. The biochemical, genetic, and molecular properties of the maize Cat2 geneenzyme system are shown in Table 1. This clone has an open reading frame encoding a 492-amino acid polypeptide that is almost identical with another Cat2 cDNA clone from maize line R6-67 (high catalase activity line) (1). Most differences are at the 5'and 3'-untranslated regions. The comparison of the Cat2 cDNA sequences and their deduced amino acid sequences from the two maize lines are shown in Figure 1. The sequence of this cDNA was 67% homologous to the maize Cat] cDNA and 72% to the maize Cat3 cDNA (4). The deduced amino acid sequence was 77% homologous to maize CAT1, 68% to CAT-3, and 41 % homologous to the rat catalase (6).}, number={4}, journal={PLANT PHYSIOLOGY}, author={GUAN, LQ and RUZSA, S and SKADSEN, RW and SCANDALIOS, JG}, year={1991}, month={Aug}, pages={1379–1381} }