title: Systems biology of GAL regulon in Saccharomyces cerevisiae.
abstract: Evolutionary success of an organism depends on its ability to express or adapt to constantly changing environmental conditions. Saccharomyces cerevisiae has evolved an elaborate genetic circuit to regulate the expression of galactose-metabolizing enzymes in the presence of galactose but in the absence of glucose. The circuit possesses molecular mechanisms such as multiple binding sites, cooperativity, autoregulation, nucleocytoplasmic shuttling, and substrate sensing mechanism. Furthermore, the GAL system consists of two positive (activating) feedback and one negative (repressing) feedback loops. These individual mechanisms, elucidated through experimental approach, can be integrated to obtain a system-wide behavior. Mathematical models in conjunction with guided experiments have demonstrated system-level properties such as ultrasensitivity, memory, noise attenuation, rapid response, and sensitive response arising out of the molecular interactions. These system-level properties allow S. cerevisiae to adapt and grow in a galactose medium under noisy and changing environments. This review focuses on system-level models and properties of the GAL regulon.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Bombay Mumbai, India 400076.
authors.forename: Venkat Reddy
authors.initials: VR
authors.lastname: Pannala
authors.affiliation: School of Bioscience and Bioengineering, Indian Institute of Technology, Bombay Mumbai, India 400076.
authors.forename: Paike Jayadeva
authors.initials: PJ
authors.lastname: Bhat
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Bombay Mumbai, India 400076.
authors.forename: Sharad
authors.initials: S
authors.lastname: Bhartiya
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Bombay Mumbai, India 400076.|School of Bioscience and Bioengineering, Indian Institute of Technology, Bombay Mumbai, India 400076.
authors.forename: K V
authors.initials: KV
authors.lastname: Venkatesh
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D018085:Regulon / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D013269:Stochastic Processes; D049490:Systems Biology / Q000379:methods*
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C050993:Galactose repressor proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins