Developmental robustness by obligate interaction of class B floral homeotic genes and proteins.
DEF-like and GLO-like class B floral homeotic genes encode closely related MADS-domain transcription factors that act as developmental switches involved in specifying the identity of petals and stamens during flower development. Class B gene function requires transcriptional upregulation by an autoregulatory loop that depends on obligate heterodimerization of DEF-like and GLO-like proteins. Because switch-like behavior of gene expression can be displayed by single genes already, the functional relevance of this complex circuitry has remained enigmatic. On the basis of a stochastic in silico model of class B gene and protein interactions, we suggest that obligate heterodimerization of class B floral homeotic proteins is not simply the result of neutral drift but enhanced the robustness of cell-fate organ identity decisions in the presence of stochastic noise. This finding strongly corroborates the view that the appearance of this regulatory mechanism during angiosperm phylogeny led to a canalization of flower development and evolution.
Lenser
Thorsten
T
Department of Computer Science, Friedrich Schiller University, Jena, Germany. thlenser@inf.uni-jena.de
Theissen
Günter
G
Dittrich
Peter
P
D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks / Q000502:physiology; D005801:Genes, Homeobox / Q000502:physiology; D017343:Genes, Plant; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism*; D019684:Magnoliopsida / Q000235:genetics* / Q000254:growth & development*; D008957:Models, Genetic; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization / Q000235:genetics; D013269:Stochastic Processes
D026161:MADS Domain Proteins; D010940:Plant Proteins