title: PRL gene expression in individual living mammotropes displays distinct functional pulses that oscillate in a noncircadian temporal pattern.
abstract: PRL gene expression in the anterior pituitary has been the focus of intensive investigation for many years, but very little information is available on the actual dynamics by which this process occurs in individual mammotrope cells. Here, we used single cell bioluminescent imaging microscopy and a recently refined reporter gene strategy to measure PRL promoter-driven gene expression (PRL-GE) in individual living primary mammotropes. Using this approach we report a new phenomenon involving repetitive on/off gene expression bursts that occurred in a distinctly noncircadian oscillatory pattern. Furthermore, we demonstrate a functional basis for these gene expression oscillations, inasmuch as PRL-GE pulses were sensitive to calcium-dependent modulation, which we show arose exclusively as changes in the shape of individual pulse episodes. Our results provide the first clear evidence that PRL-GE, in its homologous cell environment, displays oscillatory bursts of activity. Moreover, they strongly support the idea that these discrete on/off bursts of activity serve as an important determinant of the timing and level of PRL-GE under both basal and stimulated conditions.
authors.affiliation: Laboratory of Molecular Dynamics, Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors.forename: Spencer L
authors.initials: SL
authors.lastname: Shorte
authors.forename: Gilles M
authors.initials: GM
authors.lastname: Leclerc
authors.forename: Rafael
authors.initials: R
authors.lastname: Vazquez-Martinez
authors.forename: David C
authors.initials: DC
authors.lastname: Leaumont
authors.forename: William J
authors.initials: WJ
authors.lastname: Faught
authors.forename: L Stephen
authors.initials: LS
authors.lastname: Frawley
authors.forename: Fredric R
authors.initials: FR
authors.lastname: Boockfor
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D017930:Genes, Reporter / Q000235:genetics; D005822:Genetic Vectors; D015640:Ion Channel Gating / Q000502:physiology; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008163:Luminescent Measurements; D008845:Microinjections; D010507:Periodicity; D010902:Pituitary Gland / Q000166:cytology* / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011388:Prolactin / Q000096:biosynthesis* / Q000235:genetics*; D051381:Rats
chemical_list: D020746:Calcium Channels, L-Type; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D011388:Prolactin; D008156:Luciferases