A WD40 Repeat Protein Regulates Fungal Cell Differentiation and Can Be Replaced Functionally by the Mammalian Homologue Striatin

ABSTRACT Fruiting body development in fungi is a complex cellular differentiation process that is controlled by more than 100 developmental genes. Mutants of the filamentous fungus Sordaria macrospora showing defects in fruiting body formation are pertinent sources for the identification of components of this multicellular differentiation process. Here we show that the sterile mutant pro11 carries a defect in the pro11 gene encoding a multimodular WD40 repeat protein. Complementation analysis indicates that the wild-type gene or C-terminally truncated versions of the wild-type protein are able to restore the fertile phenotype in mutant pro11. PRO11 shows significant homology to several vertebrate WD40 proteins, such as striatin and zinedin, which seem to be involved in Ca2+-dependent signaling in cells of the central nervous system and are supposed to function as scaffolding proteins linking signaling and eukaryotic endocytosis. Cloning of a mouse cDNA encoding striatin allowed functional substitution of the wild-type protein with restoration of fertility in mutant pro11. Our data strongly suggest that an evolutionarily conserved cellular process controlling eukaryotic cell differentiation may regulate fruiting body formation.

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fbfB, a Gene Encoding a Putative Galactose Oxidase, Is Involved in Stigmatella aurantiacaFruiting Body Formation

Journal of Bacteriology ◽

10.1128/jb.180.5.1241-1247.1998 ◽

1998 ◽

Vol 180 (5) ◽

pp. 1241-1247 ◽

Cited By ~ 34

Author(s):

Barbara Silakowski ◽

Heidi Ehret ◽

Hans Ulrich Schairer

Keyword(s):

Fruiting Body ◽

Rhodobacter Capsulatus ◽

Fusion Gene ◽

Three Dimensional ◽

Galactose Oxidase ◽

Fruiting Bodies ◽

Wild Type ◽

Primary Alcohols ◽

Fruiting Body Formation ◽

Body Formation

ABSTRACT Stigmatella aurantiaca is a gram-negative bacterium which forms, under conditions of starvation in a multicellular process, characteristic three-dimensional structures: the fruiting bodies. For studying this complex process, mutants impaired in fruiting body formation have been induced by transposon insertion with a Tn5-derived transposon. The gene affected (fbfB) in one of the mutants (AP182) was studied further. Inactivation of fbfB results in mutants which form only clumps during starvation instead of wild-type fruiting bodies. This mutant phenotype can be partially rescued, if cells of mutants impaired in fbfB function are mixed with those of some independent mutants defective in fruiting before starvation. The fbfBgene is expressed about 14 h after induction of fruiting body formation as determined by measuring β-galactosidase activity in a merodiploid strain harboring the wild-type gene and anfbfB-Δtrp-lacZ fusion gene or by Northern (RNA) analysis with the Rhodobacter capsulatus pufBA fragment fused tofbfB as an indicator. The predicted polypeptide FbfB has a molecular mass of 57.8 kDa and shows a significant homology to the galactose oxidase (GaoA) of the fungus Dactylium dendroides. Galactose oxidase catalyzes the oxidation of galactose and primary alcohols to the corresponding aldehydes.

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In vitro stalk cell differentiation in wild-type and ‘slugger’ mutants of Dictyostelium discoideum

Development ◽

10.1242/dev.118.2.523 ◽

1993 ◽

Vol 118 (2) ◽

pp. 523-526 ◽

Cited By ~ 2

Author(s):

K. Inouye ◽

J. Gross

Keyword(s):

Dictyostelium Discoideum ◽

Fruiting Body ◽

Cell Maturation ◽

Stalk Cell ◽

Wild Type ◽

Fruiting Body Formation ◽

Body Formation ◽

Close Relationship ◽

Long Time

In ‘slugger’ mutants of Dictyostelium discoideum, aggregates of cells remain for an abnormally long time in the migratory phase under conditions where wild-type aggregates form fruiting bodies. In the present work, we have examined the relationship between the defect in fruiting body formation in these mutants and their ability to form mature stalk cells. We dissociated anterior cells from slugs of the mutants and their parents and tested their ability to form stalk cells when incubated at low density in the presence of (1) the stalk cell morphogen Differentiation Inducing Factor-1 (DIF-1) together with cyclic AMP, or (2) 8-Br-cAMP, which is believed to penetrate cell membrane and activate cAMP- dependent protein kinase (PKA). Most of the mutants were markedly defective in forming stalk cells in response to DIF-1 plus cAMP, confirming a close relationship between fruiting body formation and stalk cell maturation. On the other hand, many of these same mutants formed stalk cells efficiently in response to 8-Br-cAMP. This supports evidence for an essential role of PKA in stalk cell maturation and fruiting body formation. It also indicates that many of the mutants owe their slugger phenotype to defects in functions required for optimal adenylyl cyclase activity.

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Developmental Aggregation of Myxococcus xanthus Requires frgA, anfrz-Related Gene

Journal of Bacteriology ◽

10.1128/jb.182.23.6614-6621.2000 ◽

2000 ◽

Vol 182 (23) ◽

pp. 6614-6621 ◽

Cited By ~ 12

Author(s):

Kyungyun Cho ◽

Anke Treuner-Lange ◽

Kathleen A. O'Connor ◽

David R. Zusman

Keyword(s):

Fruiting Body ◽

Myxococcus Xanthus ◽

Complex Life Cycle ◽

Fruiting Bodies ◽

Related Gene ◽

Wild Type ◽

Fruiting Body Formation ◽

Body Formation ◽

Extracellular Signals ◽

Directed Motility

ABSTRACT Myxococcus xanthus is a gram-negative bacterium which has a complex life cycle that includes multicellular fruiting body formation. Frizzy mutants are characterized by the formation of tangled filaments instead of hemispherical fruiting bodies on fruiting agar. Mutations in the frz genes have been shown to cause defects in directed motility, which is essential for both vegetative swarming and fruiting body formation. In this paper, we report the discovery of a new gene, called frgA (forfrz-related gene), which confers a subset of the frizzy phenotype when mutated. The frgA null mutant showed reduced swarming and the formation of frizzy aggregates on fruiting agar. However, this mutant still displayed directed motility in a spatial chemotaxis assay, whereas the majority offrz mutants fail to show directed movements in this assay. Furthermore, the frizzy phenotype of the frgA mutant could be complemented extracellularly by wild-type cells or strains carrying non-frz mutations. The phenotype of the frgAmutant is similar to that of the abcA mutant and suggests that both of these mutants could be defective in the production or export of extracellular signals required for fruiting body formation rather than in the sensing of such extracellular signals. ThefrgA gene encodes a large protein of 883 amino acids which lacks homologues in the databases. The frgA gene is part of an operon which includes two additional genes, frgBand frgC. The frgB gene encodes a putative histidine protein kinase, and the frgC gene encodes a putative response regulator. The frgB and frgCnull mutants, however, formed wild-type fruiting bodies.

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Bypass of A- and B-Signaling Requirements for Myxococcus xanthus Development by Mutations in spdR

Journal of Bacteriology ◽

10.1128/jb.184.5.1455-1457.2002 ◽

2002 ◽

Vol 184 (5) ◽

pp. 1455-1457 ◽

Cited By ~ 7

Author(s):

Hubert Tse ◽

Ronald E. Gill

Keyword(s):

Fruiting Body ◽

Double Mutant ◽

Myxococcus Xanthus ◽

Wild Type ◽

Fruiting Body Formation ◽

Body Formation ◽

Factor Production

ABSTRACT Mutations in spdR, previously reported to bypass the developmental requirement for B-signaling in Myxococcus xanthus, also bypass the requirement for A-signaling but not C-, D-, or E-signaling. Mutations in spdR restored nearly wild-type levels of sporulation to representative A-signal-deficient mutants carrying asgA476, asgB480, and asgC767 and improved the quality of fruiting body formation in the asgB480 mutant. The defect in A-factor production by the asgB480 mutant was not restored in the spdR2134 asgB480 double mutant.

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Cell differentiation during fruiting body formation in polysphondylium pallidum

Journal of Cell Science ◽

10.1242/jcs.35.1.203 ◽

1979 ◽

Vol 35 (1) ◽

pp. 203-215

Author(s):

D.H. O'Day

Keyword(s):

Cell Differentiation ◽

Fruiting Body ◽

Neutral Red ◽

Immunofluorescent Staining ◽

Stalk Cell ◽

Fruiting Body Formation ◽

Body Formation ◽

Polysphondylium Pallidum ◽

Slime Moulds ◽

Cellular Slime

The spatial pattern of cellular differentiation was studied during fruiting body formation in Polysphondylium pallidum using 3 different staining methods: Calcofluor fluorescence (cellulose accumulation), neutral red (prestalk cells) and immunofluorescence (prespore cells). Neutral-red staining revealed the existence of a clear prestalk region which becomes evident during aggregation and continues throughout culmination. Immunofluorescent staining demonstrated that cells in the prestalk region gradually lose their presporeness (fluorescence) as they are transformed into differentiated stalk cells. Calcofluor staining revealed that stalk cell differentiation begins during the mid-aggregation phase and that the mode of formation of the main stalk and the side branches differs slightly in morphology. Calcofluor staining also demonstrated the development, during aggregation, of a thick cellulosic girdle with lateral tubular extensions which surround the aggregation streams. The above results are discussed in terms of our present knowledge about differentiation and morphogenesis in cellular slime moulds.

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