dictyNews

Electronic Edition

Volume 48, number 8

April 22, 2022



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Abstracts

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Novel RNAseq-informed cell-type markers and their regulation alter 

paradigms of Dictyostelium developmental control 



Gillian Forbes1, Zhi-hui Chen1, Koryu Kin1,2 and Pauline Schaap1*



1 School of Life Sciences, University of Dundee, Dundee, DD1 5EH, 

United Kingdom

2Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), 

Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain





Frontiers in Cell and Developmental Biology, in press



Cell differentiation is traditionally monitored with a few marker 

genes, which may bias results. To understand the evolution and 

regulation of the spore, stalk, cup and basal disc cells in 

Dictyostelia, we previously performed RNAseq on purified cell-

types of taxon-group representative dictyostelids. Using 

promoter-lacZ constructs in D. discoideum, we here investigate 

the spatio-temporal expression pattern of 29 cell-type specific 

genes. Genes selected for spore- or cup- specificity in RNAseq 

were validated as such by lacZ expression, but genes selected for 

stalk-specificity showed variable additional expression in basal 

disc, early cup or prestalk populations. We measured responses of 

25 genes to 15 single or combined regimes of induction by stimuli 

known to regulate cell differentiation. The outcomes of these 

experiments were subjected to hierarchical clustering to identify 

whether common modes of regulation were correlated with specific 

expression patterns. The analysis identified a cluster combining 

the spore and cup genes, which shared upregulation by 8-bromo 

cyclic AMP and down-regulation by Differentiation Inducing 

Factor 1 (DIF-1). Most stalk-expressed genes combined into a single 

cluster and shared strong upregulation by cyclic di-guanylate 

(c-di-GMP), and synergistic upregulation by combined DIF-1 and 

c-di-GMP. There was no clustering of genes expressed in other soma 

besides the stalk, but two genes that were only expressed in the 

stalk did not respond to any stimuli. In contrast to current models, 

the study indicates the existence of a stem-cell like soma 

population in slugs, whose members only acquire ultimate cell fate 

after progressing to their terminal location during fruiting body 

morphogenesis.





Submitted by Pauline Schaap [[log in to unmask]]

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[End dictyNews, volume 48, number 8]