scholarly journals Disruption of an RNA helicase/RNAse III gene in Arabidopsis causes unregulated cell division in floral meristems

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5231-5243 ◽  
Author(s):  
S.E. Jacobsen ◽  
M.P. Running ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Rna Helicase ◽  
Helicase Domain ◽  
Rnase Iii ◽  
Dead Box ◽  
Processing Event ◽  
Recessive Mutant ◽  
Floral Meristems ◽  
Axillary Inflorescence

Arabidopsis thaliana floral meristems are determinate structures that produce a defined number of organs, after which cell division ceases. A new recessive mutant, carpel factory (caf), converts the floral meristems to an indeterminate state. They produce extra whorls of stamens, and an indefinite number of carpels. Thus, CAF appears to suppress cell division in floral meristems. The function of CAF is partially redundant with the function of the CLAVATA (CLV) and SUPERMAN (SUP) genes, as caf clv and caf sup double mutants show dramatically enhanced floral meristem over-proliferation. caf mutant plants also show other defects, including absence of axillary inflorescence meristems, and abnormally shaped leaves and floral organs. The CAF gene was cloned and found to encode a putative protein of 1909 amino acids containing an N-terminal DExH/DEAD-box type RNA helicase domain attached to a C-terminal RNaseIII-like domain. A very similar protein of unknown function is encoded by a fungal and an animal genome. Helicase proteins are involved in a number of processes, including specific mRNA localization and mRNA splicing. RNase III proteins are involved in the processing of rRNA and some mRNA molecules. Thus CAF may act through some type of RNA processing event(s). CAF gives rise to two major transcripts of 2.5 and 6.2 kb. In situ hybridization experiments show that CAF RNA is expressed throughout all shoot tissues.

scholarly journals A complex containing the Sm protein CAR-1 and the RNA helicase CGH-1 is required for embryonic cytokinesis in Caenorhabditis elegans

2005 ◽  
Vol 171 (2) ◽  
pp. 267-279 ◽  
Author(s):  
Anjon Audhya ◽  
Francie Hyndman ◽  
Ian X. McLeod ◽  
Amy S. Maddox ◽  
John R. Yates ◽  
...  
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Rna Binding ◽  
Rna Binding Protein ◽  
Rna Helicase ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Daughter Cells ◽  
Sm Protein ◽  
Spindle Structure

Cytokinesis completes cell division and partitions the contents of one cell to the two daughter cells. Here we characterize CAR-1, a predicted RNA binding protein that is implicated in cytokinesis. CAR-1 localizes to germline-specific RNA-containing particles and copurifies with the essential RNA helicase, CGH-1, in an RNA-dependent fashion. The atypical Sm domain of CAR-1, which directly binds RNA, is dispensable for CAR-1 localization, but is critical for its function. Inhibition of CAR-1 by RNA-mediated depletion or mutation results in a specific defect in embryonic cytokinesis. This cytokinesis failure likely results from an anaphase spindle defect in which interzonal microtubule bundles that recruit Aurora B kinase and the kinesin, ZEN-4, fail to form between the separating chromosomes. Depletion of CGH-1 results in sterility, but partially depleted worms produce embryos that exhibit the CAR-1–depletion phenotype. Cumulatively, our results suggest that CAR-1 functions with CGH-1 to regulate a specific set of maternally loaded RNAs that is required for anaphase spindle structure and cytokinesis.

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

2017 ◽  
Vol 199 (13) ◽  
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.

scholarly journals Crystal structure of yeast initiation factor 4A, a DEAD-box RNA helicase

2000 ◽  
Vol 97 (24) ◽  
pp. 13080-13085 ◽  
Author(s):  
J. M. Caruthers ◽  
E. R. Johnson ◽  
D. B. McKay
Keyword(s):  
Crystal Structure ◽  
Rna Helicase ◽  
Initiation Factor ◽  
Dead Box

scholarly journals The embryonic RNA helicase gene (ERH): a new member of the DEAD box family of RNA helicases

1995 ◽  
Vol 308 (3) ◽  
pp. 839-846 ◽  
Author(s):  
J Sowden ◽  
W Putt ◽  
K Morrison ◽  
R Beddington ◽  
Y Edwards
Keyword(s):  
Expression Profile ◽  
Sequence Similarity ◽  
Rna Helicase ◽  
Chromosome 1 ◽  
Rna Helicases ◽  
High Sequence Similarity ◽  
Dead Box ◽  
Isolation And Characterization ◽  
Helicase Gene ◽  
The Dead

DEAD box proteins share several highly conserved motifs including the characteristic Asp-Glu-Ala-Asp (D-E-A-D in the amino acid single-letter code) motif and have established or putative ATP-dependent RNA helicase activity. These proteins are implicated in a range of cellular processes that involve regulation of RNA function, including translation initiation, RNA splicing and ribosome assembly. Here we describe the isolation and characterization of an embryonic RNA helicase gene, ERH, which maps to mouse chromosome 1 and encodes a new member of the DEAD box family of proteins. The predicted ERH protein shows high sequence similarity to the testes-specific mouse PL10 and to the maternally acting Xenopus An3 helicase proteins. The ERH expression profile is similar, to that of An3, which localizes to the animal hemisphere of oocytes and is abundantly expressed in the embryo. ERH is expressed in oocytes and is a ubiquitous mRNA in the 9 days-post-conception embryo, and at later stages of development shows a more restricted pattern of expression in brain and kidney. The similarities in sequence and in expression profile suggest that ERH is the murine equivalent of the Xenopus An3 gene, and we propose that ERH plays a role in translational activation of mRNA in the oocyte and early embryo.

A DEAD-box RNA helicase TCD33 that confers chloroplast development in rice at seedling stage under cold stress

2020 ◽  
Vol 248 ◽  
pp. 153138 ◽  
Author(s):  
Wang Xiaomei ◽  
Kong Rongrong ◽  
Zhang Ting ◽  
Gao Yuanyuan ◽  
Xu Jianlong ◽  
...  
Keyword(s):  
Cold Stress ◽  
Chloroplast Development ◽  
Rna Helicase ◽  
Seedling Stage ◽  
Dead Box

scholarly journals Regulating Intracellular Antiviral Defense and Permissiveness to Hepatitis C Virus RNA Replication through a Cellular RNA Helicase, RIG-I

2005 ◽  
Vol 79 (5) ◽  
pp. 2689-2699 ◽  
Author(s):  
Rhea Sumpter ◽  
Yueh-Ming Loo ◽  
Eileen Foy ◽  
Kui Li ◽  
Mitsutoshi Yoneyama ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Viral Infections ◽  
Cultured Cells ◽  
Rna Replication ◽  
Rna Helicase ◽  
Hcv Rna ◽  
Helicase Domain ◽  
Replication Studies ◽  
Virus Rna

ABSTRACT Virus-responsive signaling pathways that induce alpha/beta interferon production and engage intracellular immune defenses influence the outcome of many viral infections. The processes that trigger these defenses and their effect upon host permissiveness for specific viral pathogens are not well understood. We show that structured hepatitis C virus (HCV) genomic RNA activates interferon regulatory factor 3 (IRF3), thereby inducing interferon in cultured cells. This response is absent in cells selected for permissiveness for HCV RNA replication. Studies including genetic complementation revealed that permissiveness is due to mutational inactivation of RIG-I, an interferon-inducible cellular DExD/H box RNA helicase. Its helicase domain binds HCV RNA and transduces the activation signal for IRF3 by its caspase recruiting domain homolog. RIG-I is thus a pathogen receptor that regulates cellular permissiveness to HCV replication and, as an interferon-responsive gene, may play a key role in interferon-based therapies for the treatment of HCV infection.

scholarly journals A Co-Opted DEAD-Box RNA Helicase Enhances Tombusvirus Plus-Strand Synthesis

2012 ◽  
Vol 8 (2) ◽  
pp. e1002537 ◽  
Author(s):  
Nikolay Kovalev ◽  
Judit Pogany ◽  
Peter D. Nagy
Keyword(s):  
Rna Helicase ◽  
Dead Box
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