The laccase multigene family in Arabidopsis thaliana: towards addressing the mystery of their gene function(s).
While laccases, multi-copper glycoprotein oxidases, are often able to catalyze oxidation of a broad range of substrates, such as phenols and amines in vitro, their precise physiological/biochemical roles in higher plants remain largely unclear, e.g., Arabidopsis thaliana contains 17 laccases with only 1 having a known physiological function. To begin to explore their roles in planta, spatial and temporal expression patterns of Arabidopsis laccases were compared and contrasted in different tissues at various development stages using RT-PCR and promoter-GUS fusions. Various cell-specific expressions were noted where specific laccases were uniquely expressed, such as LAC4 in interfascicular fibers and seed coat columella, LAC7 in hydathodes and root hairs, LAC8 in pollen grains and phloem, and LAC15 in seed coat cell walls. Such specific cell-type expression patterns provide new leads and/or strategies into determining their precise physiological/biochemical roles. In addition, there was an apparent redundancy of gene expression patterns for several laccases across a wide variety of tissues, lignified and non-lignified, perhaps indicative of overlapping function(s). Preliminary evidence, based on bioinformatics analyses, suggests that most laccases may also be tightly regulated at both transcriptional (antisense transcripts, histone and DNA methylation) and posttranscriptional (microRNAs) levels of gene expression.
Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
Phanikanth V
PV
Turlapati
Kye-Won
KW
Kim
Laurence B
LB
Davin
Norman G
NG
Lewis
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D042845:Laccase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010641:Phenotype; D010802:Phylogeny; D018515:Plant Leaves / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D018517:Plant Roots / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D018547:Plant Stems / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D012639:Seeds / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D016415:Sequence Alignment
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D018749:RNA, Plant; D042845:Laccase