RRC ID 1869
Author Briggs GC, Mouchel CF, Hardtke CS.
Title Characterization of the plant-specific BREVIS RADIX gene family reveals limited genetic redundancy despite high sequence conservation.
Journal Plant Physiol.
Abstract To date, the function of most genes in the Arabidopsis (Arabidopsis thaliana) genome is unknown. Here we present the first analysis of the novel, plant-specific BRX (BREVIS RADIX) gene family. BRX has been identified as a modulator of root growth through a naturally occurring loss-of-function allele. The biochemical function of BRX is enigmatic, however several domains in BRX are conserved in the proteins encoded by the related BRX-like (BRXL) genes. The similarity between Arabidopsis BRXL proteins within these domains ranges from 84% to 93%. Nevertheless, analysis of brx brx-like multiple mutants indicates that functional redundancy of BRXLs is limited. This results mainly from differences in protein activity, as demonstrated by assaying the propensity of constitutively expressed BRXL cDNAs to rescue the brx phenotype. Among the genes tested, only BRXL1 can replace BRX in this assay. Nevertheless, BRXL1 does not act redundantly with BRX in vivo, presumably because it is expressed at a much lower level than BRX. BRX and BRXL1 similarity is most pronounced in a characteristic tandem repeat domain, which we named BRX domain. One copy of this domain is also present in the PRAF (PH, RCC1, and FYVE)-like family proteins. The BRX domain mediates homotypic and heterotypic interactions within and between the BRX and PRAF protein families in yeast (Saccharomyces cerevisiae), and therefore likely represents a novel protein-protein interaction domain. The importance of this domain for BRX activity in planta is underscored by our finding that expression of the C-terminal fragment of BRX, comprising the two BRX domains, is largely sufficient to rescue the brx phenotype.
Volume 140(4)
Pages 1306-16
Published 2006-4
DOI 10.1104/pp.105.075382
PII pp.105.075382
PMID 16514016
PMC PMC1435813
MeSH Alleles Amino Acid Sequence Arabidopsis / genetics* Arabidopsis / metabolism Arabidopsis Proteins / chemistry Arabidopsis Proteins / genetics* Arabidopsis Proteins / physiology Base Sequence Conserved Sequence Multigene Family / genetics Multigene Family / physiology Mutation Phylogeny Plant Roots / metabolism Protein Binding Protein Structure, Tertiary Sequence Alignment
IF 6.305
Times Cited 23
Arabidopsis / Cultured plant cells, genes pda04349 pda10162 pda10551