The Drosophila RNA Helicase Belle (DDX3) Non-Autonomously Suppresses Germline Tumorigenesis Via Regulation of a Specific mRNA Set

DDX3 subfamily DEAD-box RNA helicases are essential developmental regulators of RNA metabolism in eukaryotes. belle, the single DDX3 ortholog in Drosophila, is required for fly viability, fertility, and germline stem cell maintenance. Belle is involved both in translational activation and repression of target mRNAs in different tissues; however, direct targets of Belle in the testes are essentially unknown. Here we showed that belle RNAi knockdown in testis cyst cells caused a disruption of adhesion between germ and cyst cells and generation of tumor-like clusters of stem-like germ cells. Ectopic expression of β-integrin in cyst cells rescued early stages of spermatogenesis in belle knockdown testes, indicating that integrin adhesion complexes are required for the interaction between somatic and germ cells in a cyst. To address Belle functions in spermatogenesis in detail we performed cross-linking immunoprecipitation and sequencing (CLIP-seq) analysis and identified multiple mRNAs that interacted with Belle in the testes. The set of Belle targets includes transcripts of proteins that are essential for preventing the tumor-like clusters of germ cells and for sustaining spermatogenesis. By our hypothesis, failures in the translation of a number of mRNA targets additively contribute to developmental defects observed in the testes with belle knockdowns both in cyst cells and in the germline.

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The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells

Development ◽

10.1242/dev.101931 ◽

2013 ◽

Vol 141 (1) ◽

pp. 73-82 ◽

Cited By ~ 24

Author(s):

A. R. Shields ◽

A. C. Spence ◽

Y. M. Yamashita ◽

E. L. Davies ◽

M. T. Fuller

Keyword(s):

Stem Cell ◽

Germ Cell ◽

Binding Protein ◽

Actin Binding ◽

Germline Stem Cell ◽

Actin Binding Protein ◽

Stem Cell Maintenance ◽

Cyst Cells ◽

Cell Maintenance

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A role for Gle1, a regulator of DEAD-box RNA helicases, at centrosomes and basal bodies

Molecular Biology of the Cell ◽

10.1091/mbc.e16-09-0675 ◽

2017 ◽

Vol 28 (1) ◽

pp. 120-127 ◽

Cited By ~ 23

Author(s):

Li-En Jao ◽

Abdalla Akef ◽

Susan R. Wente

Keyword(s):

Mrna Export ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Rna Helicases ◽

Microtubule Organization ◽

Developmental Defects ◽

Dead Box ◽

Pericentriolar Material ◽

Pore Complexes ◽

And Function

Control of organellar assembly and function is critical to eukaryotic homeostasis and survival. Gle1 is a highly conserved regulator of RNA-dependent DEAD-box ATPase proteins, with critical roles in both mRNA export and translation. In addition to its well-defined interaction with nuclear pore complexes, here we find that Gle1 is enriched at the centrosome and basal body. Gle1 assembles into the toroid-shaped pericentriolar material around the mother centriole. Reduced Gle1 levels are correlated with decreased pericentrin localization at the centrosome and microtubule organization defects. Of importance, these alterations in centrosome integrity do not result from loss of mRNA export. Examination of the Kupffer’s vesicle in Gle1-depleted zebrafish revealed compromised ciliary beating and developmental defects. We propose that Gle1 assembly into the pericentriolar material positions the DEAD-box protein regulator to function in localized mRNA metabolism required for proper centrosome function.

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punt and schnurri regulate a somatically derived signal that restricts proliferation of committed progenitors in the germline

Development ◽

10.1242/dev.124.21.4383 ◽

1997 ◽

Vol 124 (21) ◽

pp. 4383-4391 ◽

Cited By ~ 8

Author(s):

E. Matunis ◽

J. Tran ◽

P. Gonczy ◽

K. Caldwell ◽

S. DiNardo

Keyword(s):

Stem Cell ◽

Germ Cells ◽

Cell Lineage ◽

Germline Stem Cell ◽

Tgf Beta ◽

Signal Transducers ◽

Daughter Cells ◽

Stem Cell Lineage ◽

Mosaic Analysis ◽

Cyst Cells

To identify regulators of stem cell lineages, we are focusing on spermatogenesis in Drosophila. In spermatogenesis, each germline stem cell divides asymmetrically, renewing itself and producing a transiently amplifying daughter, which divides four times. By screening for mutants in which daughter cells fail to stop dividing, we find that the TGF-beta signal transducers schnurri and punt are required to limit transient amplification of germ cells. Mosaic analysis demonstrates that punt and schnurri act within somatic cyst cells that surround germ cells, rather than in germ cells. Thus, a cyst-cell-derived signal restricts germ cell proliferation and this signal is initiated by input from a member of the TGF-beta superfamily. Thus, a signal relay regulates progression through the germline stem cell lineage.

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Molecular insights into RNA recognition and gene regulation by the TRIM-NHL protein Mei-P26

10.1101/2021.09.20.461029 ◽

2021 ◽

Author(s):

Anna Salerno-Kochan ◽

Andreas Horn ◽

Pritha Ghosh ◽

Chandran Nithin ◽

Anna Ko?cielniak ◽

...

Keyword(s):

Gene Expression ◽

Cell Fate ◽

Transcriptional Regulator ◽

Germline Stem Cell ◽

Rna Recognition ◽

Stem Cell Maintenance ◽

Mrna Targets ◽

Functional Differences ◽

Rna Targets ◽

Drosophila Cells

The TRIM-NHL protein Meiotic P26 (Mei-P26) acts as a regulator of cell fate in Drosophila. Its activity is critical for ovarian germline stem cell maintenance, differentiation of oocytes and spermatogenesis. Mei-P26 functions as a post-transcriptional regulator of gene expression, however, the molecular details of how its NHL domain selectively recognizes and regulates its mRNA targets have remained elusive. Here, we present the crystal structure of the Mei-P26 NHL domain at 1.6 Å resolution and identify key amino acids that confer substrate specificity and distinguish Mei-P26 from closely related TRIM-NHL proteins. Furthermore, we identify mRNA targets of Mei-P26 in cultured Drosophila cells and show that Mei-P26 can act as either a repressor or activator of gene expression on different RNA targets. Our work reveals the molecular basis of RNA recognition by Mei-P26 and the fundamental functional differences between otherwise very similar TRIM-NHL proteins.

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CPB-3 and CGH-1 localize to motile particles within dendrites in C. elegans PVD sensory neurons

BMC Research Notes ◽

10.1186/s13104-021-05730-5 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Kathrin Spendier ◽

Eugenia C. Olesnicky ◽

Daniel Forand ◽

Margaret Wolf ◽

Darrell J. Killian

Keyword(s):

Translational Control ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Rna Helicases ◽

Cytoplasmic Polyadenylation ◽

C Elegans ◽

Mrna Targets ◽

Dead Box ◽

Dendrite Development

Abstract Objective RNA-binding proteins (RBPs) are important regulators of gene expression that influence mRNA splicing, stability, localization, transport, and translational control. In particular, RBPs play an important role in neurons, which have a complex morphology. Previously, we showed that there are many RBPs that play a conserved role in dendrite development in Drosophila dendritic arborization neurons and Caenorhabditis elegans (C. elegans) PVD neurons including the cytoplasmic polyadenylation element binding proteins (CPEBs), Orb in Drosophila and CPB-3 in C. elegans, and the DEAD box RNA helicases, Me31B in Drosophila and CGH-1 in C. elegans. During these studies, we observed that fluorescently-labeled CPB-3 and CGH-1 localize to cytoplasmic particles that are motile, and our research aims to further characterize these RBP-containing particles in live neurons. Results Here we extend on previous work to show that CPB-3 and CGH-1 localize to motile particles within dendrites that move at a speed consistent with microtubule-based transport. This is consistent with a model in which CPB-3 and CGH-1 influence dendrite development through the transport and localization of their mRNA targets. Moreover, CPB-3 and CGH-1 rarely localize to the same particles suggesting that these RBPs function in discrete ribonucleoprotein particles (RNPs) that may regulate distinct mRNAs.

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Distinct Ring1b complexes defined by DEAD-box helicases and EMT transcription factors synergistically enhance E-cadherin silencing in breast cancer

Cell Death and Disease ◽

10.1038/s41419-021-03491-4 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Yawei Wang ◽

Yingying Sun ◽

Chao Shang ◽

Lili Chen ◽

Hongyu Chen ◽

...

Keyword(s):

Breast Cancer ◽

Transcription Factors ◽

Cancer Cells ◽

Epithelial Mesenchymal Transition ◽

Epigenetic Mechanism ◽

Regulation Mechanism ◽

Rna Helicases ◽

Mesenchymal Transition ◽

Dead Box ◽

E Cadherin

AbstractRing1b is a core subunit of polycomb repressive complex 1 (PRC1) and is essential in several high-risk cancers. However, the epigenetic mechanism of Ring1b underlying breast cancer malignancy is poorly understood. In this study, we showed increased expression of Ring1b promoted metastasis by weakening cell–cell adhesions of breast cancer cells. We confirmed that Ring1b could downregulate E-cadherin and contributed to an epigenetic rewiring via PRC1-dependent function by forming distinct complexes with DEAD-box RNA helicases (DDXs) or epithelial-mesenchymal transition transcription factors (EMT TFs) on site-specific loci of E-cadherin promoter. DDXs-Ring1b complexes moderately inhibited E-cadherin, which resulted in an early hybrid EMT state of epithelial cells, and EMT TFs-Ring1b complexes cooperated with DDXs-Ring1b complexes to further repress E-cadherin in mesenchymal-like cancer cells. Clinically, high expression of Ring1b with DDXs or EMT TFs predicted low levels of E-cadherin, metastatic behavior, and poor prognosis. These findings provide an epigenetic regulation mechanism of Ring1b complexes in E-cadherin expression. Ring1b complexes may be potential therapeutic targets and biomarkers for diagnosis and prognosis in invasion breast cancer.

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The Role of Ubiquitination in Regulating Embryonic Stem Cell Maintenance and Cancer Development

International Journal of Molecular Sciences ◽

10.3390/ijms20112667 ◽

2019 ◽

Vol 20 (11) ◽

pp. 2667 ◽

Cited By ~ 1

Author(s):

Dian Wang ◽

Fan Bu ◽

Weiwei Zhang

Keyword(s):

Stem Cell ◽

Embryonic Stem Cell ◽

Cancer Biology ◽

Embryonic Stem ◽

Developmental Defects ◽

Stem Cell Maintenance ◽

Substrate Protein ◽

Cellular Events ◽

Ubiquitin Conjugating Enzymes ◽

Cell Maintenance

Ubiquitination regulates nearly every aspect of cellular events in eukaryotes. It modifies intracellular proteins with 76-amino acid polypeptide ubiquitin (Ub) and destines them for proteolysis or activity alteration. Ubiquitination is generally achieved by a tri-enzyme machinery involving ubiquitin activating enzymes (E1), ubiquitin conjugating enzymes (E2) and ubiquitin ligases (E3). E1 activates Ub and transfers it to the active cysteine site of E2 via a transesterification reaction. E3 coordinates with E2 to mediate isopeptide bond formation between Ub and substrate protein. The E1-E2-E3 cascade can create diverse types of Ub modifications, hence effecting distinct outcomes on the substrate proteins. Dysregulation of ubiquitination results in severe consequences and human diseases. There include cancers, developmental defects and immune disorders. In this review, we provide an overview of the ubiquitination machinery and discuss the recent progresses in the ubiquitination-mediated regulation of embryonic stem cell maintenance and cancer biology.

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Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus

Journal of Bacteriology ◽

10.1128/jb.00135-17 ◽

2017 ◽

Vol 199 (13) ◽

Cited By ~ 15

Author(s):

Angel A. Aguirre ◽

Alexandre M. Vicente ◽

Steven W. Hardwick ◽

Daniela M. Alvelos ◽

Ricardo R. Mazzon ◽

...

Keyword(s):

Low Temperature ◽

Caulobacter Crescentus ◽

Immunoblot Analysis ◽

Rna Helicase ◽

Rnase E ◽

Rna Helicases ◽

Content Type ◽

Dead Box ◽

Rna Degradosome ◽

The Dead

ABSTRACT In diverse bacterial lineages, multienzyme assemblies have evolved that are central elements of RNA metabolism and RNA-mediated regulation. The aquatic Gram-negative bacterium Caulobacter crescentus, which has been a model system for studying the bacterial cell cycle, has an RNA degradosome assembly that is formed by the endoribonuclease RNase E and includes the DEAD-box RNA helicase RhlB. Immunoprecipitations of extracts from cells expressing an epitope-tagged RNase E reveal that RhlE, another member of the DEAD-box helicase family, associates with the degradosome at temperatures below those optimum for growth. Phenotype analyses of rhlE, rhlB, and rhlE rhlB mutant strains show that RhlE is important for cell fitness at low temperature and its role may not be substituted by RhlB. Transcriptional and translational fusions of rhlE to the lacZ reporter gene and immunoblot analysis of an epitope-tagged RhlE indicate that its expression is induced upon temperature decrease, mainly through posttranscriptional regulation. RNase E pulldown assays show that other proteins, including the transcription termination factor Rho, a second DEAD-box RNA helicase, and ribosomal protein S1, also associate with the degradosome at low temperature. The results suggest that the RNA degradosome assembly can be remodeled with environmental change to alter its repertoire of helicases and other accessory proteins. IMPORTANCE DEAD-box RNA helicases are often present in the RNA degradosome complex, helping unwind secondary structures to facilitate degradation. Caulobacter crescentus is an interesting organism to investigate degradosome remodeling with change in temperature, because it thrives in freshwater bodies and withstands low temperature. In this study, we show that at low temperature, the cold-induced DEAD-box RNA helicase RhlE is recruited to the RNA degradosome, along with other helicases and the Rho protein. RhlE is essential for bacterial fitness at low temperature, and its function may not be complemented by RhlB, although RhlE is able to complement for rhlB loss. These results suggest that RhlE has a specific role in the degradosome at low temperature, potentially improving adaptation to this condition.

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