RNA binding protein DDX5 directs tuft cell specification and function to regulate microbial repertoire and disease susceptibility in the intestine

Gut ◽  
2021 ◽  
pp. gutjnl-2021-324984
Author(s):  
Tianyun Long ◽  
Nazia Abbasi ◽  
Juan E Hernandez ◽  
Yuxin Li ◽  
Ibrahim M Sayed ◽  
...  

ObjectiveTuft cells residing in the intestinal epithelium have diverse functions. In the small intestine, they provide protection against inflammation, combat against helminth and protist infections, and serve as entry portals for enteroviruses. In the colon, they had been implicated in tumourigenesis. Commitment of intestinal progenitor cells to the tuft cell lineage requires Rho GTPase Cell Division Cycle 42 (CDC42), a Rho GTPase that acts downstream of the epidermal growth factor receptor and wingless-related integration site signalling cascades, and the master transcription factor POU class 2 homeobox 3 (POU2F3). This study investigates how this pathway is regulated by the DEAD box containing RNA binding protein DDX5 in vivo.DesignWe assessed the role of DDX5 in tuft cell specification and function in control and epithelial cell-specific Ddx5 knockout mice (DDX5ΔIEC) using transcriptomic approaches.ResultsDDX5ΔIEC mice harboured a loss of intestinal tuft cell populations, modified microbial repertoire, and altered susceptibilities to ileal inflammation and colonic tumourigenesis. Mechanistically, DDX5 promotes CDC42 protein synthesis through a post-transcriptional mechanism to license tuft cell specification. Importantly, the DDX5-CDC42 axis is parallel but distinct from the known interleukin-13 circuit implicated in tuft cell hyperplasia, and both pathways augment Pou2f3 expression in secretory lineage progenitors. In mature tuft cells, DDX5 not only promotes integrin signalling and microbial responses, it also represses gene programmes involved in membrane transport and lipid metabolism.ConclusionRNA binding protein DDX5 directs tuft cell specification and function to regulate microbial repertoire and disease susceptibility in the intestine.

2016 ◽  
Vol 44 (5) ◽  
pp. 1321-1337 ◽  
Author(s):  
Andrew R. Clark ◽  
Jonathan L.E. Dean

Twenty years ago, the first description of a tristetraprolin (TTP) knockout mouse highlighted the fundamental role of TTP in the restraint of inflammation. Since then, work from several groups has generated a detailed picture of the expression and function of TTP. It is a sequence-specific RNA-binding protein that orchestrates the deadenylation and degradation of several mRNAs encoding inflammatory mediators. It is very extensively post-translationally modified, with more than 30 phosphorylations that are supported by at least two independent lines of evidence. The phosphorylation of two particular residues, serines 52 and 178 of mouse TTP (serines 60 and 186 of the human orthologue), has profound effects on the expression, function and localisation of TTP. Here, we discuss the control of TTP biology via its phosphorylation and dephosphorylation, with a particular focus on recent advances and on questions that remain unanswered.


Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here we show that deletion of the nrp1 gene, which encodes a putative RNA-binding protein with unknown function, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the nrp1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Nrp1 are essential for its cytoplasmic localization and function. We have also found that a portion of Nrp1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Nrp1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.


2006 ◽  
Vol 17 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Maria Paola Paronetto ◽  
Francesca Zalfa ◽  
Flavia Botti ◽  
Raffaele Geremia ◽  
Claudia Bagni ◽  
...  

Translational control plays a crucial role during gametogenesis in organisms as different as worms and mammals. Mouse knockout models have highlighted the essential function of many RNA-binding proteins during spermatogenesis. Herein we have investigated the expression and function during mammalian male meiosis of Sam68, an RNA-binding protein implicated in several aspects of RNA metabolism. Sam68 expression and localization within the cells is stage specific: it is expressed in the nucleus of spermatogonia, it disappears at the onset of meiosis (leptotene/zygotene stages), and it accumulates again in the nucleus of pachytene spermatocytes and round spermatids. During the meiotic divisions, Sam68 translocates to the cytoplasm where it is found associated with the polysomes. Translocation correlates with serine/threonine phosphorylation and it is blocked by inhibitors of the mitogen activated protein kinases ERK1/2 and of the maturation promoting factor cyclinB-cdc2 complex. Both kinases associate with Sam68 in pachytene spermatocytes and phosphorylate the regulatory regions upstream and downstream of the Sam68 RNA-binding motif. Molecular cloning of the mRNAs associated with Sam68 in mouse spermatocytes reveals a subset of genes that might be posttranscriptionally regulated by this RNA-binding protein during spermatogenesis. We also demonstrate that Sam68 shuttles between the nucleus and the cytoplasm in secondary spermatocytes, suggesting that it may promote translation of specific RNA targets during the meiotic divisions.


2020 ◽  
Author(s):  
Edwin B. Corgiat ◽  
Sara M. List ◽  
J. Christopher Rounds ◽  
Anita H. Corbett ◽  
Kenneth H. Moberg

AbstractThe human ZC3H14 gene, which encodes a ubiquitously expressed polyadenosine zinc finger RNA binding protein, is mutated in an inherited form of autosomal recessive, non-syndromic intellectual disability. To gain insight into ZC3H14 neurological functions, we previously developed a Drosophila melanogaster model of ZC3H14 loss by deleting the fly ortholog, Nab2. Studies in this invertebrate model reveal that Nab2 controls final patterns of neuron projection within fully developed adult brains. Here, we examine earlier pupal stages and define roles for Nab2 in controlling the dynamic growth of axons into the developing brain mushroom bodies (MBs), which support olfactory learning and memory, and in regulating abundance of a small fraction of the total brain proteome, a portion of which is rescued by overexpression of Nab2 specifically in brain neurons. The group of Nab2-regulated brain proteins, identified by quantitative proteomic analysis, includes the microtubule binding protein Futsch, the neuronal Ig-family transmembrane protein Turtle, the glial:neuron adhesion protein Contactin, the RacGAP Tumbleweed, and the planar cell polarity factor Van Gogh, which collectively link Nab2 to a the processes of brain morphogenesis, neuroblast proliferation, circadian sleep/wake cycles, and synaptic development. Overall, these data indicate that Nab2 controls abundance of a subset of brain proteins during the active process of wiring the pupal brain mushroom body, and thus provide a window into potentially conserved functions of the Nab2/ZC3H14 RNA binding proteins in neurodevelopment and function.


2021 ◽  
Vol 22 (9) ◽  
pp. 4795
Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here, we show that deletion of the dri1 gene, which encodes a putative RNA-binding protein, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the dri1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Dri1 are essential for its cytoplasmic localization and function. We have also found that a portion of Dri1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Dri1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.


2020 ◽  
Vol 21 (15) ◽  
pp. 5209
Author(s):  
Simon Jasinski-Bergner ◽  
André Steven ◽  
Barbara Seliger

The muscle excess 3 (MEX-3) protein was first identified in Caenorhabditis elegans (C. elegans), and its respective homologues were also observed in vertebrates, including humans. It is a RNA-binding protein (RBP) with an additional ubiquitin E3 ligase function, which further acts as a post-transcriptional repressor through unknown mechanisms. In humans, MEX-3 proteins post-transcriptionally regulate a number of biological processes, including tumor immunological relevant ones. These have been shown to be involved in various diseases, including tumor diseases of distinct origins. This review provides information on the expression and function of the human MEX-3 family in healthy tissues, as well after malignant transformation. Indeed, the MEX-3 expression was shown to be deregulated in several cancers and to affect tumor biological functions, including apoptosis regulation, antigen processing, and presentation, thereby, contributing to the immune evasion of tumor cells. Furthermore, current research suggests MEX-3 proteins as putative markers for prognosis and as novel targets for the anti-cancer treatment.


Development ◽  
2014 ◽  
Vol 141 (10) ◽  
pp. 2046-2056 ◽  
Author(s):  
A. Rogulja-Ortmann ◽  
J. Picao-Osorio ◽  
C. Villava ◽  
P. Patraquim ◽  
E. Lafuente ◽  
...  

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