The Integrator subunits function in hematopoiesis by modulating Smad/BMP signaling

Tao, Shijie; Cai, Yu; Sampath, Karuna

doi:10.1242/dev.034959

Cited by 37 publications

(24 citation statements)

References 38 publications

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“…wnk1a and wnk1b mRNAs are maternally deposited, and zygotic expression of both begins as early as 10 hpf (hours post fertilization) and remains high at all stages examined. The expression of flk1/vegfr2 begins as early as the 5 to 9 somite stage (12 to 15 hpf) in the intermediate cell mass of the mesoderm [40] and the 14 to 19 somite stage (16 to 19 hpf) in the head and vessel endothelial cells [41]. Additional studies have reported that flk1/vegfr2 is expressed in the intersegmental vessels at 24 hpf [42] when the single circulatory loop in zebrafish is established [43], [44].…”

Section: Resultsmentioning

confidence: 99%

Zebrafish WNK Lysine Deficient Protein Kinase 1 (wnk1) Affects Angiogenesis Associated with VEGF Signaling

Lai

Tsai

et al. 2014

PLoS ONE

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The WNK1 (WNK lysine deficient protein kinase 1) protein is a serine/threonine protein kinase with emerging roles in cancer. WNK1 causes hypertension and hyperkalemia when overexpressed and cardiovascular defects when ablated in mice. In this study, the role of Wnk1 in angiogenesis was explored using the zebrafish model. There are two zebrafish wnk1 isoforms, wnk1a and wnk1b, and both contain all the functional domains found in the human WNK1 protein. Both isoforms are expressed in the embryo at the initiation of angiogenesis and in the posterior cardinal vein (PCV), similar to fms-related tyrosine kinase 4 (flt4). Using morpholino antisense oligonucleotides against wnk1a and wnk1b, we observed that wnk1 morphants have defects in angiogenesis in the head and trunk, similar to flk1/vegfr2 morphants. Furthermore, both wnk1a and wnk1b mRNA can partially rescue the defects in vascular formation caused by flk1/vegfr2 knockdown. Mutation of the kinase domain or the Akt/PI3K phosphorylation site within wnk1 destroys this rescue capability. The rescue experiments provide evidence that wnk1 is a downstream target for Vegfr2 (vascular endothelial growth factor receptor-2) and Akt/PI3K signaling and thereby affects angiogenesis in zebrafish embryos. Furthermore, we found that knockdown of vascular endothelial growth factor receptor-2 (flk1/vegfr2) or vascular endothelial growth factor receptor-3 (flt4/vegfr3) results in a decrease in wnk1a expression, as assessed by in situ hybridization and q-RT-PCR analysis. Thus, the Vegf/Vegfr signaling pathway controls angiogenesis in zebrafish via Akt kinase-mediated phosphorylation and activation of Wnk1 as well as transcriptional regulation of wnk1 expression.

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Section: Resultsmentioning

confidence: 99%

Zebrafish WNK Lysine Deficient Protein Kinase 1 (wnk1) Affects Angiogenesis Associated with VEGF Signaling

Lai

Tsai

et al. 2014

PLoS ONE

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“…Based upon these criteria, we asked whether the Integrator, which is a metazoan-specific RNAPII-associated multi-protein complex, might fulfill the role of the RNAPII pause release factor following EGF transcriptional activation. We had previously characterized Integrator as a multi-subunit complex that was required for the maturation of the small nuclear RNA genes (Baillat et al, 2005) but the number of studies describing the wide array of developmental defects and diseased states upon its dysfunction suggest its scope may extend beyond the biosynthesis of snRNA (Han et al, 2006; Kapp et al, 2013; Tao et al, 2009). …”

Section: Resultsmentioning

confidence: 99%

Integrator Regulates Transcriptional Initiation and Pause Release following Activation

et al. 2014

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SUMMARY Determining the factors regulating the rate limiting steps in transcriptional control is of fundamental importance to understanding the mechanisms that govern eukaryotic transcription. While studies in unicellular organisms have pointed to initiation as the rate-limiting step in transcription, a large body of work in metazoans indicates that the transition to productive transcriptional elongation may also constitute a critical step. Here, we show that the RNA polymerase II (RNAPII)-associated multi-protein complex, Integrator, plays a critical role in both initiation and the release of paused RNAPII in immediate early genes (IEGs) following transcriptional activation by epidermal growth factor (EGF) in human cells. Integrator is recruited to the IEGs in a signal-dependent manner and is required to engage the super elongation complex (SEC) in pause release. We propose a role for Integrator as an RNAPII-associated factor modulating both initiation and pause release during transcriptional activation in metazoans.

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“…RNAi-mediated depletion of IntS6 in Caenorhabditis elegans results in embryonic lethality and mitochondrial defects (15), whereas depletion of IntS5 in zebrafish using antisense morpholino oligonucleotides also results in lethality and defects in hematopoiesis (50). Finally, targeted disruption of the gene encoding mouse IntS1 results in early embryonic lethality and the accumulation of snRNA precursors (16).…”

Section: Discussionmentioning

confidence: 99%

A Subset of Drosophila Integrator Proteins Is Essential for Efficient U7 snRNA and Spliceosomal snRNA 3′-End Formation

Ezzeddine

Chen

Waltenspiel

et al. 2011

Molecular and Cellular Biology

116

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Proper gene expression relies on a class of ubiquitously expressed, uridine-rich small nuclear RNAs (snRNAs) transcribed by RNA polymerase II (RNAPII). Vertebrate snRNAs are transcribed from a unique promoter, which is required for proper 3-end formation, and cleavage of the nascent transcript involves the activity of a poorly understood set of proteins called the Integrator complex. To examine 3-end formation in Drosophila melanogaster, we developed a cell-based reporter that monitors aberrant 3-end formation of snRNA through the gain in expression of green fluorescent protein (GFP). We used this reporter in Drosophila S2 cells to determine requirements for U7 snRNA 3-end formation and found that processing was strongly dependent upon nucleotides located within the 3 stem-loop as well as sequences likely to comprise the Drosophila equivalent of the vertebrate 3 box. Substitution of the actin promoter for the snRNA promoter abolished proper 3-end formation, demonstrating the conserved requirement for an snRNA promoter in Drosophila. We tested the requirement for all Drosophila Integrator subunits and found that Integrators 1, 4, 9, and 11 were essential for 3-end formation and that Integrators 3 and 10 may be dispensable for processing. Depletion of cleavage and polyadenylation factors or of histone pre-mRNA processing factors did not affect U7 snRNA processing efficiency, demonstrating that the Integrator complex does not share components with the mRNA 3-end processing machinery. Finally, flies harboring mutations in either Integrator 4 or 7 fail to complete development and accumulate significant levels of misprocessed snRNA in the larval stages.In eukaryotes, the major transcripts produced by RNA polymerase II (RNAPII) include the polyadenylated [poly (A) ϩ ] mRNAs, the replication-dependent histone mRNAs, and the Sm class of small nuclear RNAs (snRNAs). The 3Ј ends of these three general classes of RNAs are all formed by cotranscriptional cleavage, but each one has a distinct mechanism for 3Ј-end formation (for reviews, see references 29 and 32). In poly(A) ϩ and histone pre-mRNAs there are conserved upstream and downstream sequences that flank the cleavage site; factors bind to these sites and then recruit additional factors that initiate cleavage (53). In the case of poly(A) ϩ pre-mRNA, the upstream element is the canonical AAUAAA polyadenylation signal (PAS) and the downstream sequence is the G/Urich downstream element (DSE). Recognition of the PAS is carried out by the cleavage and polyadenylation specificity complex (CPSF) component CPSF160 via its RNA recognition motifs (RRM) (36), whereas the DSE is bound by the RRM of the cleavage stimulation factor (CstF) component CstF64 (28). Subsequent to this recognition event is recruitment of additional factors that activate the endonucleolytic cleavage between the PAS and the DSE.Histone pre-mRNA contains a distinct set of flanking elements. Upstream of the cleavage site is a conserved stem-loop structure (SL) and downstream a purine-rich element called the ...

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The Integrator subunits function in hematopoiesis by modulating Smad/BMP signaling

Cited by 37 publications

References 38 publications

Zebrafish WNK Lysine Deficient Protein Kinase 1 (wnk1) Affects Angiogenesis Associated with VEGF Signaling

Zebrafish WNK Lysine Deficient Protein Kinase 1 (wnk1) Affects Angiogenesis Associated with VEGF Signaling

Integrator Regulates Transcriptional Initiation and Pause Release following Activation

A Subset of Drosophila Integrator Proteins Is Essential for Efficient U7 snRNA and Spliceosomal snRNA 3′-End Formation

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