title: Pulsatile patterns of pituitary hormone gene expression change during development.
abstract: Important questions in biology have emerged recently concerning the timing of transcription in living cells. Studies on clonal cell lines have shown that transcription is often pulsatile and stochastic, with implications for cellular differentiation. Currently, information regarding transcriptional activity at cellular resolution within a physiological context remains limited. To investigate single-cell transcriptional activity in real-time in living tissue we used bioluminescence imaging of pituitary tissue from transgenic rats in which luciferase gene expression is driven by a pituitary hormone gene promoter. We studied fetal and neonatal pituitary tissue to assess whether dynamic patterns of transcription change during tissue development. We show that gene expression in single cells is highly pulsatile at the time endocrine cells first appear but becomes stabilised as the tissue develops in early neonatal life. This stabilised transcription pattern might depend upon tissue architecture or paracrine signalling, as isolated cells, generated from enzymatic dispersion of the tissue, display pulsatile luminescence. Nascent cells in embryonic tissue also showed coordinated transcription activity over short distances further indicating that cellular context is important for transcription activity. Overall, our data show that cells alter their patterns of gene expression according to their context and developmental stage, with important implications for cellular differentiation.
authors: Developmental Biomedicine Research Group, Faculty of Medical and Human Sciences, AV Hill Building, University of Manchester, Manchester M13 9PT,  UK.
authors: Karen
authors: K
authors: Featherstone
authors: Claire V
authors: CV
authors: Harper
authors: Anne
authors: A
authors: McNamara
authors: Sabrina
authors: S
authors: Semprini
authors: David G
authors: DG
authors: Spiller
authors: Judith
authors: J
authors: McNeilly
authors: Alan S
authors: AS
authors: McNeilly
authors: John J
authors: JJ
authors: Mullins
authors: Michael R H
authors: MR
authors: White
authors: Julian R E
authors: JR
authors: Davis
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn; D002478:Cells, Cultured; D060833:Cellular Microenvironment / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D049409:Luciferases, Firefly / Q000235:genetics; D008163:Luminescent Measurements / Q000379:methods; D009024:Morphogenesis / Q000235:genetics; D010507:Periodicity; D010902:Pituitary Gland / Q000196:embryology* / Q000378:metabolism; D010907:Pituitary Hormones / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats
chemical_list: D010907:Pituitary Hormones; D049409:Luciferases, Firefly