Determinator-inhibitor pairs as a mechanism for threshold setting in development: a possible function for pseudogenes.
Thresholds are frequently thought to be involved in the development of discrete structures in response to a shallow, monotonic gradient of morphogenetic information. We propose a mechanism for threshold setting that incorporates two essential components: (i) determinator genes that produce intracellular "determinators" that control cellular differentiation during development and (ii) intracellular "inhibitors" that bind tightly and specifically to the determinators to form "determinator-inhibitor pairs" that are inactive with respect to determinator function. The interaction of these components amplifies the intracellular response to an extra-cellular morphogen, thus producing a sharp transition in determinator gene activity. This system could operate at either the RNA level with the determinator-inhibitor pairs taking the form of sense-antisense RNAs or at the protein level via a competitive inhibition mechanism. In either case this model suggests a possible role for pseudogenes in development as a source of the intracellular inhibitors.
McCarrey
J R
JR
Riggs
A D
AD
D000818:Animals; D005075:Biological Evolution; D002454:Cell Differentiation; D004330:Drosophila / Q000254:growth & development; D005796:Genes; D008433:Mathematics; D008957:Models, Genetic; D009024:Morphogenesis; D009154:Mutation; D010641:Phenotype; D012313:RNA / Q000502:physiology
D012313:RNA