title: Comparison between the Amount of Environmental Change and the Amount of Transcriptome Change.
abstract: Cells must coordinate adjustments in genome expression to accommodate changes in their environment. We hypothesized that the amount of transcriptome change is proportional to the amount of environmental change. To capture the effects of environmental changes on the transcriptome, we compared transcriptome diversities (defined as the Shannon entropy of frequency distribution) of silkworm fat-body tissues cultured with several concentrations of phenobarbital. Although there was no proportional relationship, we did identify a drug concentration "tipping point" between 0.25 and 1.0 mM. Cells cultured in media containing lower drug concentrations than the tipping point showed uniformly high transcriptome diversities, while those cultured at higher drug concentrations than the tipping point showed uniformly low transcriptome diversities. The plasticity of transcriptome diversity was corroborated by cultivations of fat bodies in MGM-450 insect medium without phenobarbital and in 0.25 mM phenobarbital-supplemented MGM-450 insect medium after previous cultivation (cultivation for 80 hours in MGM-450 insect medium without phenobarbital, followed by cultivation for 10 hours in 1.0 mM phenobarbital-supplemented MGM-450 insect medium). Interestingly, the transcriptome diversities of cells cultured in media containing 0.25 mM phenobarbital after previous cultivation (cultivation for 80 hours in MGM-450 insect medium without phenobarbital, followed by cultivation for 10 hours in 1.0 mM phenobarbital-supplemented MGM-450 insect medium) were different from cells cultured in media containing 0.25 mM phenobarbital after previous cultivation (cultivation for 80 hours in MGM-450 insect medium without phenobarbital). This hysteretic phenomenon of transcriptome diversities indicates multi-stability of the genome expression system. Cellular memories were recorded in genome expression networks as in DNA/histone modifications.
authors.affiliation: Nihon BioData Corporation, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012, Japan.
authors.forename: Norichika
authors.initials: N
authors.lastname: Ogata
authors.affiliation: Human Resource Development Program in Agricultural Genome Sciences, Tokyo University of Agriculture and Technology, 3-5-8, Saiwai-cho, Fuchu, Tokyo, 183-8501, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kozaki
authors.affiliation: Laboratory of Sericultural Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8, Saiwai-cho, Fuchu, Tokyo, 183-8501, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: National Institute of Agrobiological Sciences, Owashi 1-2, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Tamako
authors.initials: T
authors.lastname: Hata
authors.affiliation: Laboratory of Applied Entomology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8, Saiwai-cho, Fuchu, Tokyo, 183-8501, Japan.
authors.forename: Kikuo
authors.initials: K
authors.lastname: Iwabuchi
mesh_terms: D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000235:genetics*; D002478:Cells, Cultured; D059647:Gene-Environment Interaction; D016678:Genome / Q000187:drug effects; D010634:Phenobarbital / Q000494:pharmacology; D059467:Transcriptome
chemical_list: D010634:Phenobarbital