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dictyNews Volume 42 Number 06
dictyNews
Electronic Edition
Volume 42, number 6
February 26, 2016
Please submit abstracts of your papers as soon as they have been
accepted for publication by sending them to dicty@northwestern.edu
or by using the form at
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.
Back issues of dictyNews, the Dicty Reference database and other
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Abstracts
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A Continuum Model of Transcriptional Bursting
Adam M Corrigan, Edward Tunnacliffe, Danielle Cannon,
and Jonathan R Chubb*
Laboratory for Molecular Cell Biology and Division
of Cell and Developmental Biology, University College London,
Gower Street, London, WC1E 6BT.
eLife, accepted
Transcription occurs in stochastic bursts. Early models based
upon RNA hybridisation studies suggest bursting dynamics arise
from alternating inactive and permissive states. Here we
investigate bursting mechanism in live cells by quantitative
imaging of actin gene transcription, combined with molecular
genetics, stochastic simulation and probabilistic modelling.
In contrast to early models, our data indicate a continuum of
transcriptional states, with a slowly fluctuating initiation
rate converting the gene between different levels of activity,
interspersed with extended periods of inactivity. We place an
upper limit of 40s on the lifetime of fluctuations in
elongation rate, with initiation rate variations persisting
an order of magnitude longer. TATA mutations reduce the
accessibility of high activity states, leaving the lifetime
of on- and off-states unchanged. A continuum or spectrum of
gene states potentially enables a wide dynamic range for cell
responses to stimuli.
submitted by: Jonathan Chubb [j.chubb@ucl.ac.uk]
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Differentiation-inducing factor 2 modulates chemotaxis via
the histidine kinase DhkC-dependent pathway in Dictyostelium
discoideum
Hidekazu Kuwayama, Yuzuru Kubohara
HK: Faculty of Life and Environmental Sciences, University
of Tsukuba, Tsukuba 305-8572, Japan.
YK: Department of Health Science, Graduate School of Health
and Sports Science, Juntendo University, Inzai 270-1695, Japan.
FEBS Letters, in press
DIF-1 and DIF-2 are signaling molecules that control chemotaxis
in Dictyostelium discoideum. Whereas DIF-1 suppresses chemotaxis
in shallow cAMP gradients, DIF-2 enhances chemotaxis under the
same conditions via a phosphodiesterase, RegA, which is a part
of the DhkC–RdeA–RegA two-component signaling system. In this
study, to investigate the mechanism of the chemotaxis
regulation by DIF-2, we examined the effects of DIF-2
(and DIF-1) on chemotaxis in rdeA– and dhkC– mutant strains.
In the parental wild-type strains, chemotactic cell movement
was suppressed with DIF-1 and enhanced with DIF-2 in shallow
cAMP gradients. In contrast, in both rdeA– and dhkC– strains,
chemotaxis was suppressed with DIF-1 but unaffected by DIF-2.
The results suggest that DIF-2 modulates chemotaxis via the
DhkC–RdeA–RegA signaling system.
submitted by: Yuzuru Kubohara [ykuboha@juntendo.ac.jp]
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[End dictyNews, volume 42, number 6]
