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dictyNews Volume 27 Number 17
dictyNews
Electronic Edition
Volume 27, number 17
December 22, 2006
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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cAMP production by adenylyl cyclase G induces prespore differentiation
in Dictyostelium slugs
Elisa Alvarez-Curto, Shweta Saran, Marcel Meima, Jenny Zobel, Claire
Scott and Pauline Schaap*
Division of Cell and Developmental Biology, College of Life Sciences,
University of Dundee, Dundee, Angus DD1 5EH, UK
Development, in press
Encystation and sporulation are crucial developmental transitions for
solitary and social amoebas, respectively. While little is known of
encystation, sporulation requires both extra- and intracellular cAMP.
After aggregation of social amoebas, extracellular cAMP binding to surface
receptors and intracellular cAMP binding to cAMP dependent protein kinase
(PKA) act together to induce prespore differentiation. Later, a second
episode of PKA activation triggers spore maturation. Adenylyl cyclase B
(ACB) produces cAMP for maturation, but the cAMP source for prespore
induction is unknown. We show that adenylyl cyclase G (ACG) protein is
upregulated in prespore tissue after aggregation. acg null mutants show
reduced prespore differentiation, which becomes very severe when ACB is
also deleted. ACB is normally expressed in prestalk cells, but is
upregulated in the prespore region of acg null structures. These data
show that ACG induces prespore differentiation in wild-type cells, with
ACB capable of partially taking over this function in its absence.
Submitted by Pauline Schaap [p.schaap@dundee.ac.uk]
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Treasure hunt in an amoeba: non-coding RNAs in Dictyostelium discoideum
Andrea Hinas and Fredrik Soderbom
Department of Molecular Biology, Biomedical Center, Swedish University
of Agricultural Sciences, Box 590, 75124 Uppsala, Sweden
Current Genetics, in press
Review Article
Abstract The traditional view of RNA being merely an intermediate in the
transfer of genetic information, as mRNA, spliceosomal RNA, tRNA, and
rRNA, has become outdated. The recent discovery of numerous regulatory
RNAs with a plethora of functions in biological processes has truly
revolutionized our understanding of gene regulation. Tiny RNAs such as
microRNAs and small interfering RNAs play vital roles at different levels of
gene control. Small nucleolar RNAs are much more abundant than
previously recognized, and new functions beyond processing and
modification of rRNA have recently emerged. Longer non-coding RNAs
(ncRNAs) can also have important regulatory roles in the cell, e.g.,
antisense RNAs that control their target mRNAs. The majority of these i
mportant findings arose from analyses in various model organisms. In this
review, we focus on ncRNAs in the social amoeba Dictyostelium
discoideum. This important genetically tractable model organism has
recently received renewed attention in terms of discovery, regulation and
functional studies of ncRNAs. Old and recent findings are discussed and
put in context of what we today know about ncRNAs in other organisms.
Submitted by: Fredrik Soderbom [fredde@xray.bmc.uu.se]
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Dictyostelium Myb transcription factors function at culmination as activators
of ancillary stalk differentiation
Masatsune Tsujioka*, Natasha Zhukovskaya*, Yoko Yamada, Masashi
Fukuzawa, Susan Ross and Jeffrey G. Williams
*contributed equally
University of Dundee
MSI/WTB Complex
Dow Street
Dundee DD1 5EH
UK
Eukaryotic Cell in press
ecmB and mrrA are expressed in the cups that cradle Dictyostelium
spore-heads and MybE is necessary for their expression in lower but not
upper cup cells. A Myb site within the mrrA promoter is necessary for
expression in both cups. Thus multiple Myb proteins are required for
ancillary stalk differentiation.
Submitted by: Jeff Williams [j.g.williams@dundee.ac.uk]
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[End dictyNews, volume 27, number 17]
