dictyNews

Electronic Edition

Volume 46, number 12

April 24, 2020



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Abstracts

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Loss of the polyketide synthase StlB results in stalk cell overproduction 

in Polysphondylium violaceum.



Takaaki B. Narita1,2, Yoshinori Kawabe1, Koryu Kin1, Richard A. Gibbs3, 

Adam Kuspa3,4,5, Donna M. Muzny3, Stephen Richards3,7, Joan E. 

Strassmann6, Richard Sucgang3,4, Kim C. Worley3 and Pauline Schaap1*



1School of Life Sciences, University of Dundee, Dundee DD15EH, UK

2Present address: Department of Life Science, Faculty of Advanced 

Engineering, Chiba Institute of Technology, Chiba 275-0016, Japan. 

3Department of Molecular and Human Genetics   

4Verna and Marrs McLean Department of Biochemistry and Molecular 

Biology, Baylor College of Medicine, Houston, TX  77030, USA.

6Department of Biology, Washington University, St Louis, USA.

5The Welch Foundation, Houston, Texas, USA. 

7Genome Sequencing Center, University of California Davis, Davis, CA.





Genome Biology and Evolution, in press



Major phenotypic innovations in social amoeba evolution occurred at the 

transition between the Polysphondylia and group 4 Dictyostelia, which 

comprise the model organism D. discoideum (Ddis), such as the formation 

of a new structure, the basal disc. Basal disc differentiation and robust 

stalk formation requires the morphogen DIF-1, synthesized by the 

polyketide synthase StlB, the des-methyl-DIF-1 methyltransferase DmtA 

and the chlorinase ChlA, which are conserved throughout Dictyostelia. To 

understand how the basal disc and other innovations evolved in group 4, 

we sequenced and annotated the Polysphondylium violaceum (Pvio) 

genome, performed cell-type specific transcriptomics to identify cell-type 

marker genes, and developed transformation and gene knock-out 

procedures for Pvio. We used the novel methods to delete the Pvio stlB 

gene. The Pvio stlB- mutants formed misshapen curly sorogens with thick 

and irregular stalks. As fruiting body formation continued, the upper stalks 

became more regular, but structures contained 40% less spores. The stlB- 

sorogens overexpressed a stalk gene and under-expressed a (pre)spore 

gene. Normal fruiting body formation and sporulation were restored in Pvio 

stlB- by including DIF-1 in the supporting agar. These data indicate that, 

while conserved, stlB and its product(s) acquired both a novel role in the 

group 4 Dictyostelia and a role opposite to that in its sister group.





submitted by:  Pauline Schaap   [[log in to unmask]]

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Molecular networking in the neuronal ceroid lipofuscinoses: Insights from 

mammalian models and the social amoeba Dictyostelium discoideum



Robert J. Huber



Department of Biology, Trent University, Peterborough, Ontario, Canada





Journal of Biomedical Science, accepted



The neuronal ceroid lipofuscinoses (NCLs), commonly known as Batten 

disease, belong to a family of neurological disorders that cause blindness, 

seizures, loss of motor function and cognitive ability, and premature death. 

There are 13 different subtypes of NCL that are associated with mutations 

in 13 genetically distinct genes (CLN1-CLN8, CLN10-CLN14). Similar 

clinical and pathological profiles of the different NCL subtypes suggest that 

common disease mechanisms may be involved. As a result, there have been 

many efforts to determine how NCL proteins are connected at the cellular 

level. A main driving force for NCL research has been the utilization of 

mammalian and non-mammalian cellular models to study the mechanisms 

underlying the disease. One non-mammalian model that has provided 

significant insight into NCL protein function is the social amoeba 

Dictyostelium discoideum. Accumulated data from Dictyostelium and 

mammalian cells show that NCL proteins display similar localizations, have 

common binding partners, and regulate the expression and activities of one 

another. In addition, genetic models of NCL display similar phenotypes. 

This review integrates findings from Dictyostelium and mammalian models 

of NCL to highlight our understanding of the molecular networking of NCL 

proteins. The goal here is to help set the stage for future work to reveal the 

cellular mechanisms underlying the NCLs.





submitted by:  Robert Huber    [[log in to unmask]]

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[End dictyNews, volume 46, number 12]