Identification and analysis of a gene that is essential for morphogenesis and prespore cell differentiation in Dictyostelium

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2565-2576 ◽  
Author(s):  
H. Yasukawa ◽  
S. Mohanty ◽  
R.A. Firtel
Keyword(s):  
Gene Expression ◽  
Cell Differentiation ◽  
Cell Fate ◽  
Stalk Cell ◽  
Specific Gene ◽  
Wild Type ◽  
Cell Type ◽  
Primary Defect ◽  
Experimental Conditions ◽  
Prespore Cell

We have identified a gene (PslA) that is expressed throughout Dictyostelium development and encodes a novel protein that is required for proper aggregation and subsequent cell-type differentiation and morphogenesis. pslA null (pslA-) cells produce large aggregation streams under conditions in which wild-type cells form discrete aggregates. Tips form along the stream, elongate to produce a finger, and eventually form a terminal structure that lacks a true sorus (spore head). More than half of the cells remain as a mass at the base of the developing fingers. The primary defect in the pslA- strain is the inability to induce prespore cell differentiation. Analyses of gene expression show a complete lack of prespore-specific gene expression and no mature spores are produced. In chimeras with wild-type cells, pslA- cells form the prestalk domain and normal, properly proportioned fruiting bodies can be produced. This indicates that pslA- cells are able to interact with wild-type cells and regulate patterning, even though pslA- cells are unable to express prespore cell-type-specific genes, do not participate in prespore cell differentiation and do not produce pslA- spores in the chimeras. While pslA- cells produce mature, vacuolated stalk cells during multicellular development, pslA- cells are unable to do so in vitro in response to exogenous DIF (a morphogen required for prestalk and stalk cell differentiation). These results indicate that pslA- cells exhibit a defect in the prestalk/stalk cell pathways under these experimental conditions. Our results suggest that PslA's primary function is to regulate prespore cell determination very early in the prespore pathway via a cell-autonomous mechanism, possibly at the time of the initial prestalk/prespore cell-fate decision. Indirect immunofluorescence of myc-tagged PslA localizes the protein to the nucleus, suggesting that PslA may function to control the prespore pathway at the level of transcription.

scholarly journals Expression of an activated rasD gene changes cell fate decisions during Dictyostelium development.

1997 ◽  
Vol 8 (2) ◽  
pp. 303-312 ◽  
Author(s):  
S A Louis ◽  
G B Spiegelman ◽  
G Weeks
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Cell Mass ◽  
Cell Formation ◽  
Specific Gene ◽  
Wild Type ◽  
Multicellular Development ◽  
Cell Fate Decisions ◽  
Prespore Cell

It has been previously demonstrated that the expression of an activated rasD gene in wild-type Dictyostelium cells results in formation of aggregates with multitips, instead of the normal single tips, and a block in further development. In an attempt to better understand the role of activated RasD development, we examined cell-type-specific gene expression in a strain stably expressing high levels of RasD[G12T]. We found that the expression of prestalk cell-specific genes ecmA and tagB was markedly enhanced, whereas the expression of the prespore cell-specific gene cotC was reduced to very low levels. When the fate of cells in the multitipped aggregate was monitored with an ecmA/lacZ fusion, it appeared that most of the cells eventually adopted prestalk gene expression characteristics. When mixtures of the [G12T]rasD cells and Ax3 cells were induced to differentiate, chimeric pseudoplasmodia were not formed. Thus, although the [G12T]rasD transformant had a marked propensity to form prestalk cells, it could not supply the prestalk cell population when mixed with wild-type cells. Both stalk and spore cell formation occurred in low cell density monolayers of the [G12T]rasD strain, suggesting that at least part of the inhibition of stalk and spore formation during multicellular development involved inhibitory cell interactions within the cell mass. Models for the possible role of rasD in development are discussed.

scholarly journals Functional Promiscuity of Gene Regulation by Serpentine Receptors in Dictyostelium discoideum

1998 ◽  
Vol 18 (10) ◽  
pp. 5744-5749 ◽  
Author(s):  
Irene Verkerke-Van Wijk ◽  
Ji-Yun Kim ◽  
Raymond Brandt ◽  
Peter N. Devreotes ◽  
Pauline Schaap
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Dictyostelium Discoideum ◽  
Developmental Regulation ◽  
Mutant Cell ◽  
Gene Induction ◽  
Specific Gene ◽  
Wild Type ◽  
Animal Development ◽  
Camp Stimulation

ABSTRACT Serpentine receptors such as smoothened and frizzled play important roles in cell fate determination during animal development. InDictyostelium discoideum, four serpentine cyclic AMP (cAMP) receptors (cARs) regulate expression of multiple classes of developmental genes. To understand their function, it is essential to know whether each cAR is coupled to a specific gene regulatory pathway or whether specificity results from the different developmental regulation of individual cARs. To distinguish between these possibilities, we measured gene induction in car1 car3 double mutant cell lines that express equal levels of either cAR1, cAR2, or cAR3 under a constitutive promoter. We found that all cARs efficiently mediate both aggregative gene induction by cAMP pulses and induction of postaggregative and prespore genes by persistent cAMP stimulation. Two exceptions to this functional promiscuity were observed. (i) Only cAR1 can mediate adenosine inhibition of cAMP-induced prespore gene expression, a phenomenon that was found earlier in wild-type cells. cAR1’s mediation of adenosine inhibition suggests that cAR1 normally mediates prespore gene induction. (ii) Only cAR2 allows entry into the prestalk pathway. Prestalk gene expression is induced by differentiation-inducing factor (DIF) but only after cells have been prestimulated with cAMP. We found that DIF-induced prestalk gene expression is 10 times higher in constitutive cAR2 expressors than in constitutive cAR1 or cAR3 expressors (which still have endogenous cAR2), suggesting that cAR2 mediates induction of DIF competence. Since in wild-type slugs cAR2 is expressed only in anterior cells, this could explain the so far puzzling observations that prestalk cells differentiate at the anterior region but that DIF levels are actually higher at the posterior region. After the initial induction of DIF competence, cAMP becomes a repressor of prestalk gene expression. This function can again be mediated by cAR1, cAR2, and cAR3.

scholarly journals A Ubiquitin-Conjugating Enzyme Is Essential for Developmental Transitions in Dictyostelium

1997 ◽  
Vol 8 (10) ◽  
pp. 1989-2002 ◽  
Author(s):  
Alexandra Clark ◽  
Anson Nomura ◽  
Sudhasri Mohanty ◽  
Richard A. Firtel
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Specific Gene ◽  
Wild Type ◽  
Cell Type ◽  
Protein Ubiquitination ◽  
High Amino Acid ◽  
Cell Type Specific ◽  
Very High

We have identified a developmentally essential gene,UbcB, by insertional mutagenesis. The encoded protein (UBC1) shows very high amino acid sequence identity to ubiquitin-conjugating enzymes from other organisms, suggesting that UBC1 is involved in protein ubiquitination and possibly degradation during Dictyostelium development. Consistent with the homology of the UBC1 protein to UBCs, the developmental pattern of protein ubiquitination is altered in ubcB-null cells.ubcB-null cells are blocked in the ability to properly execute the developmental transition that occurs between the induction of postaggregative gene expression during mound formation and the induction of cell-type differentiation and subsequent morphogenesis.ubcB-null cells plated on agar form mounds with normal kinetics; however, they remain at this stage for ∼10 h before forming multiple tips and fingers that then arrest. Under other conditions, some of the fingers form migrating slugs, but no culmination is observed. In ubcB-null cells, postaggregative gene transcripts accumulate to very high levels and do not decrease significantly with time as they do in wild-type cells. Expression of cell-type-specific genes is very delayed, with the level of prespore-specific gene expression being significantly reduced compared with that in wild-type cells. lacZ reporter studies using developmentally regulated and cell-type-specific promoters suggest that ubcB-null cells show an unusually elevated level of staining of lacZ reporters expressed in anterior-like cells, a regulatory cell population found scattered throughout the aggregate, and reduced staining of a prespore reporter.ubcB-null cells in a chimeric organism containing predominantly wild-type cells are able to undergo terminal differentiation but show altered spatial localization. In contrast, in chimeras containing only a small fraction of wild-type cells, the mature fruiting body is very small and composed almost exclusively of wild-type cells, with the ubcB-null cells being present as a mass of cells located in extreme posterior of the developing organism. The amino acid sequence analysis of the UbcBopen reading frame (ORF) and the analysis of the developmental phenotypes suggest that tip formation and subsequent development requires specific protein ubiquitination, and possibly degradation.

scholarly journals Super-Enhancers and CTCF in Early Embryonic Cell Fate Decisions

2021 ◽  
Vol 9 ◽  
Author(s):  
Puja Agrawal ◽  
Sridhar Rao
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Critical Role ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Cell Type ◽  
Mammalian Development ◽  
Cell Fate Decisions ◽  
Cell Type Specific ◽  
Early Mammalian Development

Cell fate decisions are the backbone of many developmental and disease processes. In early mammalian development, precise gene expression changes underly the rapid division of a single cell that leads to the embryo and are critically dependent on autonomous cell changes in gene expression. To understand how these lineage specifications events are mediated, scientists have had to look past protein coding genes to the cis regulatory elements (CREs), including enhancers and insulators, that modulate gene expression. One class of enhancers, termed super-enhancers, is highly active and cell-type specific, implying their critical role in modulating cell-type specific gene expression. Deletion or mutations within these CREs adversely affect gene expression and development and can cause disease. In this mini-review we discuss recent studies describing the potential roles of two CREs, enhancers and binding sites for CTCF, in early mammalian development.

scholarly journals H3K4 mono- and di-methyltransferase MLL4 is required for enhancer activation during cell differentiation

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Ji-Eun Lee ◽  
Chaochen Wang ◽  
Shiliyang Xu ◽  
Young-Wook Cho ◽  
Lifeng Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Cell Differentiation ◽  
Functional Redundancy ◽  
Model Systems ◽  
Specific Gene ◽  
Cell Type ◽  
Specific Gene Expression ◽  
Cell Type Specific ◽  
Differentiation Stage

Enhancers play a central role in cell-type-specific gene expression and are marked by H3K4me1/2. Active enhancers are further marked by H3K27ac. However, the methyltransferases responsible for H3K4me1/2 on enhancers remain elusive. Furthermore, how these enzymes function on enhancers to regulate cell-type-specific gene expression is unclear. In this study, we identify MLL4 (KMT2D) as a major mammalian H3K4 mono- and di-methyltransferase with partial functional redundancy with MLL3 (KMT2C). Using adipogenesis and myogenesis as model systems, we show that MLL4 exhibits cell-type- and differentiation-stage-specific genomic binding and is predominantly localized on enhancers. MLL4 co-localizes with lineage-determining transcription factors (TFs) on active enhancers during differentiation. Deletion of Mll4 markedly decreases H3K4me1/2, H3K27ac, Mediator and Polymerase II levels on enhancers and leads to severe defects in cell-type-specific gene expression and cell differentiation. Together, these findings identify MLL4 as a major mammalian H3K4 mono- and di-methyltransferase essential for enhancer activation during cell differentiation.

scholarly journals The Interplay Between Chromatin Architecture and Lineage-Specific Transcription Factors and the Regulation of Rag Gene Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Kazuko Miyazaki ◽  
Masaki Miyazaki
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Specific Gene ◽  
Cell Type ◽  
Cell Fate Decisions ◽  
Chromatin Architecture ◽  
Cell Type Specific

Cell type-specific gene expression is driven through the interplay between lineage-specific transcription factors (TFs) and the chromatin architecture, such as topologically associating domains (TADs), and enhancer-promoter interactions. To elucidate the molecular mechanisms of the cell fate decisions and cell type-specific functions, it is important to understand the interplay between chromatin architectures and TFs. Among enhancers, super-enhancers (SEs) play key roles in establishing cell identity. Adaptive immunity depends on the RAG-mediated assembly of antigen recognition receptors. Hence, regulation of the Rag1 and Rag2 (Rag1/2) genes is a hallmark of adaptive lymphoid lineage commitment. Here, we review the current knowledge of 3D genome organization, SE formation, and Rag1/2 gene regulation during B cell and T cell differentiation.

scholarly journals Abberant chemotaxis and differentiation in Dictyostelium mutant fgdC with a defective regulation of receptor-stimulated phosphoinositidase C

1991 ◽  
Vol 100 (4) ◽  
pp. 825-831 ◽  
Author(s):  
A.A. Bominaar ◽  
F. Kesbeke ◽  
B.E. Snaar-Jagalska ◽  
D.J. Peters ◽  
P. Schaap ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Guanylate Cyclase ◽  
Specific Gene ◽  
Wild Type ◽  
Cell Type ◽  
Surface Receptors ◽  
Cell Type Specific ◽  
Stimulation Of

Dictyostelium cells use extracellular cyclic AMP both as a chemoattractant and as a morphogen inducing cell-type-specific gene expression. Cyclic AMP binds to surface receptors, activates one or more G-proteins, and stimulates adenylate cyclase, guanylate cyclase and phosphoinositidase C. Mutant fgdC showed aberrant chemotaxis, and was devoid of cyclic AMP-induced gene expression and differentiation. Both the receptor- and G-protein-mediated stimulation of adenylate cyclase and guanylate cyclase were unaltered in mutant fgdC as compared to wild-type cells. In wild-type cells phosphoinositidase C was activated about twofold by the cyclic AMP receptor. In mutant fgdC cells, however, the enzyme was inhibited by about 60%. These results suggest that phosphoinositidase C is regulated by a receptor-operated activation/inhibition switch that is defective in mutant fgdC. We conclude that activation of phosphoinositidase C is essential for Dictyostelium development.

scholarly journals An integrated analysis of cell-type specific gene expression reveals genes regulated by REVOLUTA and KANADI1 in the Arabidopsis shoot apical meristem

PLoS Genetics ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. e1008661 ◽  
Author(s):  
Hasthi Ram ◽  
Sudeep Sahadevan ◽  
Nittaya Gale ◽  
Monica Pia Caggiano ◽  
Xiulian Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Integrated Analysis ◽  
Specific Gene ◽  
Cell Type ◽  
Specific Gene Expression ◽  
Cell Type Specific

Increased hemangioblast commitment, not vascular disorganization, is the primary defect in flt-1 knock-out mice

Development ◽  
1999 ◽  
Vol 126 (13) ◽  
pp. 3015-3025 ◽  
Author(s):  
G.H. Fong ◽  
L. Zhang ◽  
D.M. Bryce ◽  
J. Peng
Keyword(s):  
Endothelial Cells ◽  
Population Density ◽  
Cell Fate ◽  
Vascular System ◽  
Primitive Streak ◽  
Cellular Level ◽  
Wild Type ◽  
Primary Defect ◽  
Knock Out ◽  
Vascular Channels

We previously demonstrated the essential role of the flt-1 gene in regulating the development of the cardiovascular system. While the inactivation of the flt-1 gene leads to a very severe disorganization of the vascular system, the primary defect at the cellular level was unknown. Here we report a surprising finding that it is an increase in the number of endothelial progenitors that leads to the vascular disorganization in flt-1(−/−) mice. At the early primitive streak stage (prior to the formation of blood islands), hemangioblasts are formed much more abundantly in flt-1(−/−) embryos. This increase is primarily due to an alteration in cell fate determination among mesenchymal cells, rather than to increased proliferation, migration or reduced apoptosis of flt-1(−/−) hemangioblasts. We further show that the increased population density of hemangioblasts is responsible for the observed vascular disorganization, based on the following observations: (1) both flt-1(−/−) and flt-1(+/+) endothelial cells formed normal vascular channels in chimaeric embryos; (2) wild-type endothelial cells formed abnormal vascular channels when their population density was significantly increased; and (3) in the absence of wild-type endothelial cells, flt-1(−/−) endothelial cells alone could form normal vascular channels when sufficiently diluted in a developing embryo. These results define the primary defect in flt-1(−/−) embryos at the cellular level and demonstrate the importance of population density of progenitor cells in pattern formation.

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