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dictyNews Volume 29 Number 03
dictyNews
Electronic Edition
Volume 29, number 3
July 20, 2007
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
useful information is available at dictyBase - http://dictybase.org.
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Abstracts
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Note: The Hirata et al. abstract from last week's dictyNews had an error
in the title. The corrected version is below.
Involvements of a novel protein, DIA2, in cAMP signaling and spore
differentiation during Dictyostelium development
Kaori Hirata, Aiko Amagai, Soo-Cheon Chae , Shigenori Hirose¤ and
Yasuo Maeda*
Department of Developmental Biology and Neurosciences, Graduate School of
Life Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan
*Author for correspondence
Present address: Department of Pathology, Wonkwang University, Iksan-shi,
Chonbuk 570-749, South Korea
¤Present address: Departments of Molecular and Human Genetics, Biochemistry
and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
Differentiation, in press
The novel gene dia2 (differentiation-associated gene 2) was originally
isolated as a gene expressed specifically in response to initial
differentiation of Dictyostelium discoideum Ax-2 cells. Using dia2AS cells
in which the dia2 expression was inactivated by the antisense RNA method,
DIA2 protein was found to be required for cAMP signaling during cell
aggregation. During late development, the DIA2 protein changed its location
from the endoplasmic reticulum (ER) to prespore-specific vacuoles (PSVs)
that are specifically present in prespore cells at the slug. In
differentiating prestalk cells, however, DIA2 was found to be nearly lost
from the cells. Importantly, exocytosis of PSVs from prespore cells and the
subsequent spore differentiation were almost completely impaired in dia2AS
cells. In addition, spore induction by externally applied 8-bromo cAMP was
significantly suppressed in dia2AS cells. Taken together these results
strongly suggested that DIA2 might be closely involved in cAMP signaling
and spore differentiation as well as in the initiation of differentiation
during Dictyostelium development.
Submitted by: Yasuo Maeda [ymaeda@mail.tains.tohoku.ac.jp]
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Recent advances using green and red fluorescent protein variants
Annette Muller-Taubenberger1 and Kurt I. Anderson2
1) Institut fuer Zellbiologie (ABI), Ludwig-Maximilians-Universitaet Muenchen,
Schillerstr. 42, D-80336 Muenchen, Germany
2) Beatson Institute for Cancer Research, Garscube Estate Switchback Road,
Glasgow, G61 1BD, United Kingdom
Applied Microbiology and Biotechnology, in press
Fluorescent proteins have proven to be excellent tools for live cell imaging.
In addition to green fluorescent protein (GFP) and its variants, recent
progress has led to the development of monomeric red fluorescent proteins
(mRFPs) that show improved properties in respect to maturation, brightness,
and the monomeric state. This review considers green and red spectral variants,
their paired use for live cell imaging in vivo, in vitro, and in fluorescence
resonance energy transfer (FRET) studies, in addition to other recent
Òtwo colorÓ advances including photo-switching and bi-molecular fluorescence
complementation (BiFC). It will be seen that green and red fluorescent proteins
now exist with nearly ideal properties for dual-color microscopy and FRET.
Submitted by: Annette Muller-Taubenberger [amueller@lrz.uni-muenchen.de]
--------------------------------------------------------------------------------
The Golgi associated protein GRASP is required for unconventional protein
secretion during development.
Matthew A. Kinseth, Christophe Anjard, Danny Fuller, Gianni Guizzunti,
William F. Loomis, and Vivek Malhotra.
Cell and Developmental Biology , Division of Biological Sciences, University
of California San Diego, La Jolla, California 92093
Cell, in press
During Dictyostelium development, prespore cells secrete Acyl CoA binding
protein (AcbA). Upon release, AcbA is processed to generate a peptide called
SDF-2, which triggers terminal differentiation of spore cells. We have found
that cells lacking GRASP, a protein attached peripherally to the cytoplasmic
surface of Golgi membranes, fail to secrete AcbA, and thus produce inviable
spores. Surprisingly, AcbA lacks a signal sequence and is not secreted via
the conventional secretory pathway [endoplasmic reticulum-Golgi-cell surface].
GRASP is not required for conventional protein secretion, growth, and the
viability of vegetative cells. Our findings reveal a physiological role of
GRASP and provide a means to understand unconventional secretion and its
role in development.
Submitted by: Bill Loomis [wloomis@ucsd.edu]
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[End dictyNews, volume 29, number 3]
