A maternal product of the Punch locus of Drosophila melanogaster is required for precellular blastoderm nuclear divisions

1994 ◽  
Vol 107 (12) ◽  
pp. 3501-3513 ◽  
Author(s):  
X. Chen ◽  
E.R. Reynolds ◽  
G. Ranganayakulu ◽  
J.M. O'Donnell
Keyword(s):  
Drosophila Melanogaster ◽  
Mitotic Spindles ◽  
Guanosine Triphosphate ◽  
Protein Levels ◽  
Stage Of Development ◽  
Essentially Normal ◽  
Chromosome Separation ◽  
Oocyte Cytoplasm ◽  
Mitotic Figures ◽  
Pteridine Biosynthesis

The Punch locus of Drosophila melanogaster encodes the pteridine biosynthesis enzyme guanosine triphosphate cyclohydrolase. One class of Punch mutants is defective for a maternal function that results in embryonic death. We demonstrate here that the embryos exhibit nuclear division defects during the precellular blastoderm stage of development. These defects include abnormal nuclear distribution, mitotic asynchrony, and persisting chromatin bridges. Daughter nuclei that do not complete chromosome separation nevertheless initiate new interphase and mitotic cycles. As a result, interconnected mitotic figures are observed. Mitotic spindles and nuclear envelopes appear essentially normal. A mutant phenocopy was induced in wild-type embryos by treatment with the guanosine triphosphate cyclohydrolase inhibitor, 2,4-diamino-6-hydroxypyrimidine, at a very early cleavage stage. Furthermore, an inhibitor of a terminal step in pteridine biosynthesis produced an identical phenotype. Immunolocalization experiments define expression of Punch protein in nurse cells during oogenesis. The protein is packaged into granules as it is transported into the oocyte cytoplasm. As syncytial blastoderm nuclear divisions proceed, Punch protein levels decrease and disappear by cellularization. Defects in the expression of the protein in Punch maternal effect mutants correlate well with the early phenotypes. These results show that a Punch product is directly involved in early nuclear divisions and suggest a possible role in chromosome separation.

Correlation of guanosine triphosphate cyclohydrolase activity and the synthesis of pterins in Drosophila melanogaster

1976 ◽  
Vol 14 (3-4) ◽  
pp. 271-280 ◽  
Author(s):  
C. L. Fan ◽  
L. M. Hall ◽  
A. J. Skrinska ◽  
G. M. Brown
Keyword(s):  
Drosophila Melanogaster ◽  
Guanosine Triphosphate

DNA sequence, structure, and tyrosine kinase activity of the Drosophila melanogaster Abelson proto-oncogene homolog

1988 ◽  
Vol 8 (2) ◽  
pp. 843-853
Author(s):  
M J Henkemeyer ◽  
R L Bennett ◽  
F B Gertler ◽  
F M Hoffmann
Keyword(s):  
Drosophila Melanogaster ◽  
Tyrosine Kinase ◽  
Dna Sequence ◽  
Kinase Activity ◽  
Essential Gene ◽  
Sequence Similarity ◽  
Homologous Region ◽  
Loss Of Function ◽  
Tyrosine Kinase Activity ◽  
Stage Of Development

We report our molecular characterization of the Drosophila melanogaster Abelson gene (abl), a gene in which recessive loss-of-function mutations result in lethality at the pupal stage of development. This essential gene consists of 10 exons extending over 26 kilobase pairs of genomic DNA. The DNA sequence encodes a protein of 1,520 amino acids with strong sequence similarity to the human c-abl proto-oncogene beginning in the type lb 5' exon and extending through the region essential for tyrosine kinase activity. When the tyrosine kinase homologous region was expressed in Escherichia coli, phosphorylation of proteins on tyrosine residues was observed with an antiphosphotyrosine antibody. These results show that the abl gene is highly conserved through evolution and encodes a functional tyrosine protein kinase required for Drosophila development.

Zygotic expression of the pebble locus is required for cytokinesis during the postblastoderm mitoses of Drosophila

Development ◽  
1992 ◽  
Vol 114 (1) ◽  
pp. 165-171 ◽  
Author(s):  
G. Hime ◽  
R. Saint
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Regulation ◽  
Single Cells ◽  
Embryonic Cell ◽  
Cell Cycles ◽  
Drosophila Embryogenesis ◽  
Zygotic Transcription ◽  
Homozygous Mutant ◽  
Mitotic Figures

Mutations at the pebble locus of Drosophila melanogaster result in embryonic lethality. Examination of homozygous mutant embryos at the end of embryogenesis revealed the presence of fewer and larger cells which contained enlarged nuclei. Characterization of the embryonic cell cycles using DAPI, propidium iodide, anti-tubulin and anti-spectrin staining showed that the first thirteen rapid syncytial nuclear divisions proceeded normally in pebble mutant embryos. Following cellularization, the postblastoderm nuclear divisions occurred (mitoses 14, 15 and 16), but cytokinesis was never observed. Multinucleate cells and duplicate mitotic figures were seen within single cells at the time of the cycle 15 mitoses. We conclude that zygotic expression of the pebble gene is required for cytokinesis following cellularization during Drosophila embryogenesis. We postulate that developmental regulation of zygotic transcription of the pebble gene is a consequence of the transition from syncytial to cellular mitoses during cycle 14 of embryogenesis.

scholarly journals Viral Infection and Stress Affect Protein Levels of Dicer 2 and Argonaute 2 in Drosophila melanogaster

2020 ◽  
Vol 11 ◽  
Author(s):  
Alessandro Torri ◽  
Vanesa Mongelli ◽  
Juan A. Mondotte ◽  
Maria-Carla Saleh
Keyword(s):  
Drosophila Melanogaster ◽  
Viral Infection ◽  
Argonaute 2 ◽  
Protein Levels

scholarly journals Immunolocalization of the Bcl-2 protein within hematopoietic neoplasms

Blood ◽  
1991 ◽  
Vol 78 (4) ◽  
pp. 1062-1068 ◽  
Author(s):  
M Zutter ◽  
D Hockenbery ◽  
GA Silverman ◽  
SJ Korsmeyer
Keyword(s):  
Cell Survival ◽  
Large Cell ◽  
Hematologic Malignancies ◽  
Lymphocytic Leukemia ◽  
Myelogenous Leukemia ◽  
Protein Levels ◽  
Stage Of Development ◽  
T Cell Lymphomas ◽  
A Cell ◽  
Reactive Hyperplasia

Abstract The Bcl-2 proto-oncogene was discovered at the t(14;18) breakpoint found in most follicular B-cell lymphomas and some diffuse large-cell lymphomas. Bcl-2 is unique among proto-oncogenes, being localized to mitochondria and extending cell survival by blocking programmed cell death. We examined Bcl-2 protein expression in 82 hematologic malignancies and reactive lymphoid processes. All lymphomas with Bcl-2 rearrangement demonstrated high levels of Bcl-2 protein. However, most follicular and diffuse lymphomas without Bcl-2 rearrangement also displayed intense Bcl-2 staining. In these cases, mechanisms other than classic translocation may be deregulation Bcl-2. The pattern of Bcl-2 staining in follicular lymphoma is the inverse of the pattern in reactive hyperplasia, confirming a role for Bcl-2 immunolocalization in routine diagnosis. Small lymphocytic malignancies, including small lymphocytic lymphoma, mantle zone lymphoma, and chronic lymphocytic leukemia, expressed intermediate levels of Bcl-2. Bcl-2 protein varied in plasma cell dyscrasias. Bcl-2 protein levels in T-cell lymphomas reflected their corresponding stage of development. No substantial Bcl- 2 was present in the Reed-Sternberg cells of nodular sclerosing Hodgkin's disease. Chronic myelogenous leukemia was strongly positive for Bcl-2, consistent with the presence of Bcl-2 in normal myeloid progenitors. Immunohistochemistry identified an expanded spectrum of hematopoietic neoplasms in which Bcl-2 may provide a cell survival advantage.

Chronic continuous hypoxia decreases the expression of SLC4A7 (NBCn1) and SLC4A10 (NCBE) in mouse brain

2007 ◽  
Vol 293 (6) ◽  
pp. R2412-R2420 ◽  
Author(s):  
Li-Ming Chen ◽  
Inyeong Choi ◽  
Gabriel G. Haddad ◽  
Walter F. Boron
Keyword(s):  
Mouse Brain ◽  
Chronic Hypoxia ◽  
Ph Regulation ◽  
Protein Abundance ◽  
Ph Homeostasis ◽  
Acid Base ◽  
Protein Levels ◽  
Stage Of Development ◽  
Wide Range ◽  
The Central Nervous System

In the mammalian CNS, hypoxia causes a wide range of physiological effects, and these effects often depend on the stage of development. Among the effects are alterations in pH homeostasis. Na+-coupled HCO3− transporters can play critical roles in intracellular pH regulation and several, such as NCBE and NBCn1, are expressed abundantly in the central nervous system. In the present study, we examined the effect of chronic continuous hypoxia on the expression of two electroneutral Na-coupled HCO3− transporters, SLC4a7 (NBCn1) and SLC4a10 (NCBE), in mouse brain, the first such study on any acid-base transporter. We placed the mice in normobaric chambers and either maintained normoxia (21% inspired O2) or imposed continuous chronic hypoxia (11% O2) for a duration of either 14 days or 28 days, starting from ages of either postnatal age 2 days (P2) or P90. We assessed protein abundance by Western blot analysis, loading equal amounts of total protein for each condition. In most cases, hypoxia reduced NBCn1 levels by 20–50%, and NCBE levels by 15–40% in cerebral cortex, subcortex, cerebellum, and hippocampus, both after 14 and 28 days, and in both pups and adults. We hypothesize that these decreases, which are out of proportion to the expected overall decreases in brain protein levels, may especially be important for reducing energy consumption.

scholarly journals Development and lifespan duration of Drosophila melanogaster at the larval development under hypoxia and hyperoxia

2018 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Life Expectancy ◽  
Life Span ◽  
Developmental Stage ◽  
Developmental Theory ◽  
Maximum Life Span ◽  
Atmospheric Air ◽  
Average Lifespan ◽  
Stage Of Development ◽  
Development Duration

Various environmental factors can affect metabolic processes, physiological parameters and the lifespan of the whole organism. Since aging can be considered as part of development in accordance with the "developmental theory of aging", we can assume that development duration correlates with adult lifespan. Understanding how organisms react to different concentrations of O2 is an area of intense scientific study. It is known that ambient oxygen level affects body size, growth and development rates, cell cycle duration in Drosophila melanogaster, but data on the impact on lifespan remain controversial. In this study, we studied the influence of hypoxia (10% O2) and hyperoxia (40% O2) at the larval stage of development on the duration of Drosophila development and lifespan. Drosophila kept in atmospheric air (21% O2) was used as control. At the imago stage all the flies were kept in atmospheric air conditions. The results were presented as survival curves and average and maximum lifespan were calculated. The development duration of Drosophila melanogaster, which were kept under hypoxia, increased by one day compared to control and did not change at hyperoxia. Average and maximum life span significantly decreased at hyperoxia (average – by 17% in males and 10% in females, maximum – by 17% in males, p<0,001). Hypoxia in different ways influenced males and females. The average lifespan of males did not significantly change and the maximum – increased by 11% (p<0.001). In females, hypoxia during development led to a decrease in average lifespan by 18% and in maximum life span by 8%. The data obtained during our investigation allow us to conclude that the concentration of oxygen in the environment at the stage of development of Drosophila affects their life expectancy at the stage of imago, which can be explained by epigenetic mechanisms. Hyperoxia at the developmental stage adversely affected the life expectancy of fruit flies, probably due to the adverse effects of free-radical processes. Sex differences in the effects of hypoxia at the developmental stage were revealed. In female flies, it led to negative effects, while in males development under hypoxic conditions extended life span, probably due to the phenomenon of hormesis.

scholarly journals Effect of Methanolic Extract of Caryota no Seed on Geotactic Behaviour and Fecundity in Drosophila melanogaster

2020 ◽  
pp. 38-48
Author(s):  
Chinonye A. Maduagwuna ◽  
Simeon Omale ◽  
Monday A. Etuh ◽  
Steven S. Gyang
Keyword(s):  
Drosophila Melanogaster ◽  
Total Protein ◽  
Methanolic Extract ◽  
Negative Geotaxis ◽  
Protein Levels ◽  
Methanolic Extracts ◽  
Plateau State ◽  
Minute Duration ◽  
Rate Of Emergence

Aims: To investigate the effect of the methanolic extracts of Caryota no (CN) seeds negative geotaxis, fecundity and acetylcholinesterase (AChE) using Drosophila melanogaster (DM).                                                                                                      Study Design: Experimental design. Place and Duration: Sample: African Centre of Excellence for Phytomedicine Research and Development, University of Jos, Jos Plateau State Nigeria between June 2018 and February 2019                                                                                                  Methodology: 50 flies were exposed in each vial to the following concentrations: 300 mg, 350 mg, 400 mg, 500 mg and 600 mg of methanolic extracts in 5 replicates for 7 days with daily recording of mortality. Total protein assays were carried out by Randox method from the supernatant from homogenized whole flies. In vivo antioxidant activity study was conducted by measuring level of acetylcholinesterase (AChE) enzyme activity from supernatants of whole fly homogenates using a spectrophotometer at specific wavelengths over a 2 minute duration. The values were derived as part of the total protein value. Negative geotaxis was done by the climbing assay and fecundity was examined by rate of emergence of larva after exposure of the flies to treatment. The statistical difference among test groups was presumed at P < .05. Results: The methanolic extract of CN caused nonsignificant (P = .33) decrease in total protein levels compared to the control. There were also nonsignificant decreases in AChE (P = .30) activity, negative geotactic (P = .80) behaviour and nonsignificant increase in fecundity (P = .17) in the methanolic extract-treated flies compared to the controls. Conclusion: It can therefore be concluded that the methanolic extract of Caryota no nonsignificantly improved fertitity and reduced negative geotaxis and AChE activity in DM.

scholarly journals Control of pre-replicative complex during the division cycle in Chlamydomonas reinhardtii

PLoS Genetics ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. e1009471
Author(s):  
Amy E. Ikui ◽  
Noriko Ueki ◽  
Kresti Pecani ◽  
Frederick R. Cross
Keyword(s):  
Dna Replication ◽  
Proteasome Inhibition ◽  
Transcriptional Level ◽  
Temperature Sensitive ◽  
Mitotic Spindles ◽  
Protein Levels ◽  
Multiple Fission ◽  
Mcm Helicase ◽  
Replication Control ◽  
Living Organisms

DNA replication is fundamental to all living organisms. In yeast and animals, it is triggered by an assembly of pre-replicative complex including ORC, CDC6 and MCMs. Cyclin Dependent Kinase (CDK) regulates both assembly and firing of the pre-replicative complex. We tested temperature-sensitive mutants blocking Chlamydomonas DNA replication. The mutants were partially or completely defective in DNA replication and did not produce mitotic spindles. After a long G1, wild type Chlamydomonas cells enter a division phase when it undergoes multiple rapid synchronous divisions (‘multiple fission’). Using tagged transgenic strains, we found that MCM4 and MCM6 were localized to the nucleus throughout the entire multiple fission division cycle, except for transient cytoplasmic localization during each mitosis. Chlamydomonas CDC6 was transiently localized in nucleus in early division cycles. CDC6 protein levels were very low, probably due to proteasomal degradation. CDC6 levels were severely reduced by inactivation of CDKA1 (CDK1 ortholog) but not the plant-specific CDKB1. Proteasome inhibition did not detectably increase CDC6 levels in the cdka1 mutant, suggesting that CDKA1 might upregulate CDC6 at the transcriptional level. All of the DNA replication proteins tested were essentially undetectable until late G1. They accumulated specifically during multiple fission and then were degraded as cells completed their terminal divisions. We speculate that loading of origins with the MCM helicase may not occur until the end of the long G1, unlike in the budding yeast system. We also developed a simple assay for salt-resistant chromatin binding of MCM4, and found that tight MCM4 loading was dependent on ORC1, CDC6 and MCM6, but not on RNR1 or CDKB1. These results provide a microbial framework for approaching replication control in the plant kingdom.

scholarly journals Disruption in A-to-I editing levels affects C. elegans development more than a complete lack of editing

2018 ◽  
Author(s):  
Nabeel S. Ganem ◽  
Noa Ben-Asher ◽  
Aidan C. Manning ◽  
Sarah N. Deffit ◽  
Michael C. Washburn ◽  
...  
Keyword(s):  
Rna Editing ◽  
Phenotypic Diversity ◽  
Abnormal Development ◽  
C Elegans ◽  
Protein Levels ◽  
Stage Of Development ◽  
Extended Lifespan ◽  
Gene Regulatory ◽  
Adar Gene ◽  
Editing Process

SummaryA-to-I RNA editing is widespread in eukaryotic transcriptomes and plays an essential role in the creation of proteomic and phenotypic diversity. Loss of ADARs, the proteins responsible for A-to-I editing, results in lethality in mammals. In C. elegans, knocking out both ADARs, ADR-1 and ADR-2, results in aberrant behavior and abnormal development. Studies have shown that ADR-2 can actively deaminate dsRNA while ADR-1 cannot. However, as most studies of C. elegans ADARs were performed on worms mutated in both ADAR genes, the effects observed cannot be attributed to a single ADAR or to the interactions between ADAR genes. Therefore, we set to study the effects of each C. elegans ADAR on RNA editing, gene expression, protein levels and the contribution of each of ADAR to the phenotypes observed in worms mutated in both genes, in order to elucidate their distinct functions. We found significant differences in the phenotypes observed in worms mutated in a single ADAR gene. Worms harboring adr-1 mutations have a significant reduction in their lifespan, while worms harboring adr-2 mutations have extended lifespan. We also observed severe abnormalities in vulva formation in adr-1 mutants, and we suggest that these phenotypes are a result of an RNA editing independent function of ADR-1. Mutations in each ADAR resulted in expressional changes in hundreds of genes, and a significant downregulation of edited genes. However, very few changes in the protein levels were observed. In addition, we found that ADR-1 binds many edited genes and primarily promotes editing at the L4 stage of development. While editing still occurs in the absence of ADR-1, most of the editing occurs in genes that are edited in wildtype worms, suggesting that ADR-1 does not prevent editing by binding to and protecting the RNA but rather enhances or promotes editing. Our results suggest that ADR-1 plays a significant role in the RNA editing process and by altering editing levels it causes the severe phenotypes that we observed. In contrast, a complete lack of RNA editing is less harmful to the worms. Furthermore, our results indicate that the effect of RNA editing on the protein content in the cell is minor and probably the main purpose of these modifications is to antagonize or enhance other gene regulatory mechanisms that act on RNA.

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