Activation of the easter zymogen is regulated by five other genes to define dorsal-ventral polarity in the Drosophila embryo

Development ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 607-616 ◽  
Author(s):  
R. Chasan ◽  
Y. Jin ◽  
K.V. Anderson
Keyword(s):  
Maternal Effect ◽  
Serine Proteases ◽  
Drosophila Embryo ◽  
Vitelline Membrane ◽  
Mutant Form ◽  
Wild Type ◽  
Zymogen Activation ◽  
Embryonic Polarity ◽  
Dominant Mutant ◽  
Maternal Effect Genes

The product of the Drosophila easter gene, a member of the trypsin family of serine proteases, must be more active ventrally than dorsally to promote normal embryonic polarity. The majority of the easter protein in the embryo is present in the unprocessed zymogen form and appears to be evenly distributed in the extracellular space, indicating that the asymmetric activity of wild-type easter must arise post-translationally. A dominant mutant form of easter that does not require cleavage of the zymogen for activity (ea delta N) is active both dorsally and ventrally. The ea delta N mutant bypasses the requirement for five other maternal effect genes, indicating that these five genes exert their effects on dorsal-ventral patterning solely by controlling the activation of the easter zymogen. We propose that dorsal-ventral asymmetry is initiated by a ventrally-localized molecule in the vitelline membrane that nucleates an easter zymogen activation complex, leading to the production of ventrally active easter enzyme.

Analysis of maternal effect mutant combinations elucidates regulation and function of the overlap of hunchback and Kruppel gene expression in the Drosophila blastoderm embryo

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 651-662 ◽  
Author(s):  
U. Gaul ◽  
H. Jackle
Keyword(s):  
Maternal Effect ◽  
Drosophila Embryo ◽  
Homeotic Genes ◽  
Protein Distribution ◽  
Wild Type ◽  
Gap Gene ◽  
Gap Genes ◽  
Underlying Mechanisms ◽  
And Function ◽  
Pair Rule

The metameric organisation of the Drosophila embryo is generated early during development, due to the action of maternal effect and zygotic segmentation and homeotic genes. The gap genes participate in the complex process of pattern formation by providing a link between the maternal and the zygotic gene activities. Under the influence of maternal gene products they become expressed in distinct domains along the anteroposterior axis of the embryo; negative interactions between neighboring gap genes are thought to be involved in establishing the expression domains. The gap gene activities in turn are required for the correct patterning of the pair-rule genes; little is known, however, about the underlying mechanisms. We have monitored the distribution of gap and pair-rule genes in wild-type embryos and in embryos in which the anteroposterior body pattern is greatly simplified due to combinations of maternal effect mutations (staufen exuperantia, vasa exuperantia, vasa exuperantia, bicoid oskar, bicoid oskar torsolike, vasa torso exuperantia). We show that the domains of protein distribution of the gap genes hunchback and Kruppel overlap in wild-type embryos. Based on the analysis of the maternal mutant combinations, we suggest an explanation of how this overlap is generated. Furthermore, our data show that different constellations of gap gene activities provide different input for the pair-rule genes, and thus strongly suggest that the overlap of hunchback and Kruppel in wild-type is functional in the formation of the patterns of pair-rule genes.

Spatial regulation of Drosophila snake protease activity in the generation of dorsal-ventral polarity

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4127-4135 ◽  
Author(s):  
C.L. Smith ◽  
H. Giordano ◽  
M. Schwartz ◽  
R. DeLotto
Keyword(s):  
Serine Proteases ◽  
Signal Transduction Pathway ◽  
Positional Information ◽  
Biochemical Properties ◽  
Site Directed Mutagenesis ◽  
Drosophila Embryo ◽  
Perivitelline Space ◽  
Zymogen Activation

Positional information along the dorsal-ventral axis of the Drosophila embryo is acquired through a signal transduction pathway which employs a extracellular protease cascade. The sequential activation of serine protease zymogens results in the ventrally localized production of a ligand in the perivitelline space of the embryo. Snake is one of several serine proteases which function in generating the ventralizing signal. Here, we investigate the biochemical properties of Snake in vivo and in vitro using recombinant forms of the protease. Wild-type Snake zymogen completely rescues embryos from snake null females when microinjected into the perivitelline space. Biochemical evidence for a covalently associated two-chain form of the activated protease is presented. The contribution of the activation peptide region to zymogen activation was addressed using site-directed mutagenesis. The phenotypic rescue properties of an autoactivated form of Snake reveal that the covalently associated proenzyme polypeptide chain suppresses a dominant effect associated with the activated catalytic chain alone. Recombinant active catalytic chain was produced and found to be short lived as a recombinant protein. These results suggest a model in which the proenzyme polypeptide both stabilizes and targets the Snake catalytic chain to a ventrally localized activation complex within the perivitelline space.

scholarly journals THE GENETICS OF THE DORSAL-BICAUDAL-D REGION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 113 (3) ◽  
pp. 665-678
Author(s):  
Ruth Steward ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Maternal Effect ◽  
Complementation Group ◽  
Drosophila Embryo ◽  
Temperature Sensitive ◽  
X Ray ◽  
Dominant Phenotype ◽  
Maternal Effect Genes ◽  
D Region ◽  
Complementation Groups ◽  
Anterior Posterior

ABSTRACT The chromosomal region 36C on 2L contains two maternal-effect loci, dorsal (dl) and Bicaudal-D (Bic-D), which are involved in establishing polarity of the Drosophila embryo along the dorsal-ventral and anterior-posterior axes, respectively. To analyze the region genetically, we isolated X-ray-induced dorsal alleles, which we recognized by virtue of the haplo-insufficient temperature-sensitive dorsal-dominant phenotype in progeny of single females heterozygous for a mutagenized chromosome. From the 20,000 chromosomes tested, we isolated three deficiencies, two inversions with breakpoint in dl and one apparent dl point mutant. One of the deficiencies, Df(2L)H20 (36A6,7; 36F1,2) was used to screen for EMS-induced lethal- and maternal-effect mutants mapping in the vicinity of dl and Bic-D. We isolated 44 lethal mutations defining 11 complementation groups. We also recovered as maternal-effect mutations four dl alleles, as well as six alleles of quail and one allele of kelch, two previously identified maternal-effect genes. Through complementation tests with various viable mutants and deficiencies in the region, a total of 18 loci were identified in an interval of about 30 cytologically visible bands. The region was subdivided into seven subregions by deficiency breakpoints. One lethal complementation group as well as the two maternal loci, Bic-D and quail, are located in the same deficiency interval as is dl.

Positive and negative regulation of Easter, a member of the serine protease family that controls dorsal-ventral patterning in the Drosophila embryo

Development ◽  
1998 ◽  
Vol 125 (7) ◽  
pp. 1261-1267 ◽  
Author(s):  
S. Misra ◽  
P. Hecht ◽  
R. Maeda ◽  
K.V. Anderson
Keyword(s):  
Serine Proteases ◽  
Feedback Loop ◽  
Early Embryo ◽  
High Molecular Mass ◽  
Drosophila Embryo ◽  
Zymogen Activation ◽  
Cell Fates ◽  
Biochemical Processes ◽  
Serine Protease Family

The sequential activities of four members of the trypsin family of extracellular serine proteases are required for the production of the ventrally localized ligand that organizes the dorsal-ventral pattern of the Drosophila embryo. The last protease in this sequence is encoded by easter, which is a candidate to activate proteolytically the ligand encoded by spatzle. Here, we demonstrate biochemically that the zymogen form of Easter is processed in vivo by a proteolytic cleavage event that requires the three upstream proteases. Processed Easter is present in extremely low amounts in the early embryo because it is rapidly converted into a high molecular mass complex, which may contain a protease inhibitor. Easter zymogen activation is also controlled by a negative feedback loop from Dorsal, the transcription factor at the end of the signaling pathway. Each of these regulated biochemical processes is likely to be important in generating the ventral-to-dorsal gradient of Dorsal protein that organizes cell fates in the early embryo.

Mutants in the Saccharomyces cerevisiae RAS2 gene influence life span, cytoskeleton, and regulation of mitosis

1997 ◽  
Vol 43 (8) ◽  
pp. 774-781 ◽  
Author(s):  
Alena Pichová ◽  
Dagmar Vondráková ◽  
Michael Breitenbach
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Span ◽  
Morphological Analysis ◽  
Mutant Form ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Dominant Mutant ◽  
Cytoplasmic Microtubules ◽  
Mother Cells ◽  
Mutant Cells

We investigated the phenotypic consequences in Saccharomyces cerevisiae of a disruption allele (ras2::LEU2) and of a dominant mutant form (RAS2ala18,val19) of RAS2. In addition to the phenotypes described earlier for these mutants, we observed a small increase in the life span for the disruption allele and a drastic decrease of life span for the dominant mutant form, as compared with the isogenic wild type. This was found by analyzing these alleles in two different genetic backgrounds with nearly the same results. Life spans were determined by micromanipulating mother cells and counting generations until no further cell division occurred. A morphological analysis of the terminal phenotypes of very old mother cells was performed showing enlarged or rounded cells and in some cases elongated buds, some of which were difficult to separate from the mother cell. This was observed in wild-type cells, as well as mutant cells. However, the dominant RAS2 mutant (but not the wild-type or ras2::LEU2 mutant cells) after 2 days on complex media displayed phenotypes similar to the terminal phenotype of old mothers. A substantial fraction of the cells were enlarged and generated elongated buds, they lost Calcofluor staining of the bud scars, the cell surface appeared folded, the actin cytoskeleton was aberrant, and the mitotic spindle and the cytoplasmic microtubules were defective in their proper orientation, resulting in aberrant mitoses and empty buds. These phenotypic characteristics of the RAS2ala18,val19 mutation could be causative for the previously observed rapid loss of viability of these cells in stationary phase.Key words: yeast, Saccharomyces cerevisiae, RAS, oncogene, aging, morphology.

scholarly journals Wild-Type and Mutant FUS Expression Reduce Proliferation and Neuronal Differentiation Properties of Neural Stem Progenitor Cells

2021 ◽  
Vol 22 (14) ◽  
pp. 7566
Author(s):  
Eleonora Stronati ◽  
Stefano Biagioni ◽  
Mario Fiore ◽  
Mauro Giorgi ◽  
Giancarlo Poiana ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Progenitor Cells ◽  
Neuronal Differentiation ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Nervous System Development ◽  
Mutant Form ◽  
Wild Type ◽  
Fused In Sarcoma ◽  
Glial Lineage

Nervous system development involves proliferation and cell specification of progenitor cells into neurons and glial cells. Unveiling how this complex process is orchestrated under physiological conditions and deciphering the molecular and cellular changes leading to neurological diseases is mandatory. To date, great efforts have been aimed at identifying gene mutations associated with many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Mutations in the RNA/DNA binding protein Fused in Sarcoma/Translocated in Liposarcoma (FUS/TLS) have been associated with motor neuron degeneration in rodents and humans. Furthermore, increased levels of the wild-type protein can promote neuronal cell death. Despite the well-established causal link between FUS mutations and ALS, its role in neural cells remains elusive. In order to shed new light on FUS functions we studied its role in the control of neural stem progenitor cell (NSPC) properties. Here, we report that human wild-type Fused in Sarcoma (WT FUS), exogenously expressed in mouse embryonic spinal cord-derived NSPCs, was localized in the nucleus, caused cell cycle arrest in G1 phase by affecting cell cycle regulator expression, and strongly reduced neuronal differentiation. Furthermore, the expression of the human mutant form of FUS (P525L-FUS), associated with early-onset ALS, drives the cells preferentially towards a glial lineage, strongly reducing the number of developing neurons. These results provide insight into the involvement of FUS in NSPC proliferation and differentiation into neurons and glia.

scholarly journals Variants in Maternal Effect Genes and Relaxed Imprinting Control in a Special Placental Mesenchymal Dysplasia Case with Mild Trophoblast Hyperplasia

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 544
Author(s):  
Tien-Chi Huang ◽  
Kung-Chao Chang ◽  
Jen-Yun Chang ◽  
Yi-Shan Tsai ◽  
Yao-Jong Yang ◽  
...  
Keyword(s):  
Maternal Effect ◽  
Hydatidiform Mole ◽  
Placental Tissue ◽  
Differentially Methylated Region ◽  
Normal Birth ◽  
Maternal Effect Genes ◽  
Common Etiology ◽  
Artificial Abortion ◽  
Secondary Dmr ◽  
Placental Mesenchymal Dysplasia

Placental mesenchymal dysplasia (PMD) and partial hydatidiform mole (PHM) placentas share similar characteristics, such as placental overgrowth and grape-like placental tissues. Distinguishing PMD from PHM is critical because the former can result in normal birth, while the latter diagnosis will lead to artificial abortion. Aneuploidy and altered dosage of imprinted gene expression are implicated in the pathogenesis of PHM and also some of the PMD cases. Diandric triploidy is the main cause of PHM, whereas mosaic diploid androgenetic cells in the placental tissue have been associated with the formation of PMD. Here, we report a very special PMD case also presenting with trophoblast hyperplasia phenotype, which is a hallmark of PHM. This PMD placenta has a normal biparental diploid karyotype and is functionally sufficient to support normal fetal growth. We took advantage of this unique case to further dissected the potential common etiology between these two diseases. We show that the differentially methylated region (DMR) at NESP55, a secondary DMR residing in the GNAS locus, is significantly hypermethylated in the PMD placenta. Furthermore, we found heterozygous mutations in NLRP2 and homozygous variants in NLRP7 in the mother’s genome. NLRP2 and NLRP7 are known maternal effect genes, and their mutation in pregnant females affects fetal development. The variants/mutations in both genes have been associated with imprinting defects in mole formation and potentially contributed to the mild abnormal imprinting observed in this case. Finally, we identified heterozygous mutations in the X-linked ATRX gene, a known maternal–zygotic imprinting regulator in the patient. Overall, our study demonstrates that PMD and PHM may share overlapping etiologies with the defective/relaxed dosage control of imprinted genes, representing two extreme ends of a spectrum.

scholarly journals Familial Parkinson's Disease Mutant E46K α-Synuclein Localizes to Membranous Structures, Forms Aggregates, and Induces Toxicity in Yeast Models

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Michael Fiske ◽  
Michael White ◽  
Stephanie Valtierra ◽  
Sara Herrera ◽  
Keith Solvang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Plasma Membrane ◽  
Mutant Form ◽  
Phospholipid Membrane ◽  
Endomembrane System ◽  
Wild Type ◽  
Significant Toxicity ◽  
Familial Parkinson’S Disease

In Parkinson’s disease (PD), midbrain dopaminergic neuronal death is linked to the accumulation of aggregated α-synuclein. The familial PD mutant form of α-synuclein, E46K, has not been thoroughly evaluated yet in an organismal model system. Here, we report that E46K resembled wild-type (WT) α-synuclein in Saccharomyces cerevisiae in that it predominantly localized to the plasma membrane, and it did not induce significant toxicity or accumulation. In contrast, in Schizosaccharomyces pombe, E46K did not associate with the plasma membrane. Instead, in one strain, it extensively aggregated in the cytoplasm and was as toxic as WT. Remarkably, in another strain, E46K extensively associated with the endomembrane system and was more toxic than WT. Our studies recapitulate and extend aggregation and phospholipid membrane association properties of E46K previously observed in vitro and cell culture. Furthermore, it supports the notion that E46K generates toxicity partly due to increased association with endomembrane systems within cells.

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