VP16-activation of the C. elegans neural specification transcription factor UNC-86 suppresses mutations in downstream genes and causes defects in neural migration and axon outgrowth

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1159-1168 ◽  
Author(s):  
J.Y. Sze ◽  
Y. Liu ◽  
G. Ruvkun
Keyword(s):  
Transcription Factor ◽  
Homeobox Gene ◽  
Regulatory Sequences ◽  
General Strategy ◽  
Cell Fates ◽  
C Elegans ◽  
Expression Of Genes ◽  
Normal Expression ◽  
Neural Specification ◽  
And Function

The POU homeobox gene unc-86 specifies many neuroblast and neural fates in the developing C. elegans nervous system. Genes regulated by unc-86 are mostly unknown. Here we describe a genetic strategy for the identification of downstream pathways regulated by unc-86. We activate UNC-86 transcription activity by inserting the VP16 activation domain into an unc-86 genomic clone that bears all regulatory sequences necessary for normal expression in C. elegans. unc-86/VP16 complements unc-86 mutations in the specification of neuroblast and neural cell fates, but displays novel genetic activities: it can suppress non-null mutations in the downstream genes mec-3 and mec-7 that are necessary for mechanosensory neuron differentiation and function. These data suggest that UNC-86/VP16 increases the expression of mec-3 and mec-7 to compensate for the decreased activities of mutant MEC-3 or MEC-7 proteins. The suppression of mutations in downstream genes by an activated upstream transcription factor should be a general strategy for the identification of genes in transcriptional cascades. unc-86/VP16 also causes neural migration and pathfinding defects and novel behavioral defects. Thus, increased or unregulated expression of genes downstream of unc-86 can confer novel neural phenotypes suggestive of roles for unc-86-regulated genes in neural pathfinding and function. Genetic suppression of these unc-86/VP16 phenotypes may identify the unc-86 downstream genes that mediate these events in neurogenesis.

The Caenorhabditis elegans lim-6 LIM homeobox gene regulates neurite outgrowth and function of particular GABAergic neurons

Development ◽  
1999 ◽  
Vol 126 (7) ◽  
pp. 1547-1562 ◽  
Author(s):  
O. Hobert ◽  
K. Tessmar ◽  
G. Ruvkun
Keyword(s):  
Epithelial Cells ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Acid Decarboxylase ◽  
Neural Function ◽  
C Elegans ◽  
Gaba Synthesis ◽  
And Function ◽  
Rate Limiting ◽  
Enteric Muscle

We describe here the functional analysis of the C. elegans LIM homeobox gene lim-6, the ortholog of the mammalian Lmx-1a and b genes that regulate limb, CNS, kidney and eye development. lim-6 is expressed in a small number of sensory-, inter- and motorneurons, in epithelial cells of the uterus and in the excretory system. Loss of lim-6 function affects late events in the differentiation of two classes of GABAergic motorneurons which control rhythmic enteric muscle contraction. lim-6 is required to specify the correct axon morphology of these neurons and also regulates expression of glutamic acid decarboxylase, the rate limiting enzyme of GABA synthesis in these neurons. Moreover, lim-6 gene activity and GABA signaling regulate neuroendocrine outputs of the nervous system. In the chemosensory system lim-6 regulates the asymmetric expression of a probable chemosensory receptor. lim-6 is also required in epithelial cells for uterine morphogenesis. We compare the function of lim-6 to those of other LIM homeobox genes in C. elegans and suggest that LIM homeobox genes share the common theme of controlling terminal neural differentiation steps that when disrupted lead to specific neuroanatomical and neural function defects.

Regulation of ectodermal and excretory function by the C. elegans POU homeobox gene ceh-6

Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 779-790 ◽  
Author(s):  
T.R. Burglin ◽  
G. Ruvkun
Keyword(s):  
Transcription Factor ◽  
Epithelial Cells ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Null Mutant ◽  
Reporter Construct ◽  
Excretory Function ◽  
C Elegans ◽  
Gfp Reporter ◽  
Excretory Cell

Caenorhabditis elegans has three POU homeobox genes, unc-86, ceh-6 and ceh-18. ceh-6 is the ortholog of vertebrate Brn1, Brn2, SCIP/Oct6 and Brn4 and fly Cf1a/drifter/ventral veinless. Comparison of C. elegans and C. briggsae CEH-6 shows that it is highly conserved. C. elegans has only three POU homeobox genes, while Drosophila has five that fall into four families. Immunofluorescent detection of the CEH-6 protein reveals that it is expressed in particular head and ventral cord neurons, as well as in rectal epithelial cells, and in the excretory cell, which is required for osmoregulation. A deletion of the ceh-6 locus causes 80% embryonic lethality. During morphogenesis, embryos extrude cells in the rectal region of the tail or rupture, indicative of a defect in the rectal epithelial cells that express ceh-6. Those embryos that hatch are sick and develop vacuoles, a phenotype similar to that caused by laser ablation of the excretory cell. A GFP reporter construct expressed in the excretory cell reveals inappropriate canal structures in the ceh-6 null mutant. Members of the POU-III family are expressed in tissues involved in osmoregulation and secretion in a number of species. We propose that one evolutionary conserved function of the POU-III transcription factor class could be the regulation of genes that mediate secretion/osmoregulation.

scholarly journals Wnt signaling mediates oncogenic synergy between Akt and Dlx5 in T-cell lymphomagenesis by enhancing cholesterol synthesis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yinfei Tan ◽  
Eleonora Sementino ◽  
Zemin Liu ◽  
Kathy Q. Cai ◽  
Joseph R. Testa
Keyword(s):  
Transcription Factor ◽  
T Cell ◽  
Cholesterol Synthesis ◽  
Regulatory Element ◽  
Cholesterol Biosynthesis ◽  
Homeobox Gene ◽  
Rna Seq ◽  
Expression Of Genes ◽  
Highly Sensitive ◽  
Sterol Regulatory Element

Abstract The Dlx5 homeobox gene was first implicated as an oncogene in a T-ALL mouse model expressing myristoylated (Myr) Akt2. Furthermore, overexpression of Dlx5 was sufficient to drive T-ALL in mice by directly activating Akt and Notch signaling. These findings implied that Akt2 cooperates with Dlx5 in T-cell lymphomagenesis. To test this hypothesis, Lck-Dlx5;Lck-MyrAkt2 transgenic mice were generated. MyrAkt2 synergized with Dlx5 to greatly accelerate and enhance the dissemination of T-lymphomagenesis. RNA-seq analysis performed on lymphomas from Lck-Dlx5;Lck-MyrAkt mice revealed upregulation of genes involved in the Wnt and cholesterol biosynthesis pathways. Combined RNA-seq and ChIP-seq analysis of lymphomas from Lck-Dlx5;Lck-MyrAkt mice demonstrated that β-catenin directly regulates genes involved in sterol regulatory element binding transcription factor 2 (Srebf2)-cholesterol synthesis. These lymphoma cells had high Lef1 levels and were highly sensitive to β-catenin and Srebf2-cholesterol synthesis inhibitors. Similarly, human T-ALL cell lines with activated NOTCH and AKT and elevated LEF1 levels were sensitive to inhibition of β-catenin and cholesterol pathways. Furthermore, LEF1 expression positively correlated with expression of genes involved in the cholesterol synthesis pathway in primary human T-ALL specimens. Together, these data suggest that targeting β-catenin and/or cholesterol biosynthesis, together with AKT, could have therapeutic efficacy in a subset of T-ALL patients.

scholarly journals Peptide affinity analysis of proteins that bind to an unstructured NH2-terminal region of the osmoprotective transcription factor NFAT5

2016 ◽  
Vol 48 (4) ◽  
pp. 290-305 ◽  
Author(s):  
Jenna F. DuMond ◽  
Kevin Ramkissoon ◽  
Xue Zhang ◽  
Yuichiro Izumi ◽  
Xujing Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Terminal Region ◽  
Hek293 Cells ◽  
The Novel ◽  
Amino Acid Peptide ◽  
Intrinsically Disordered ◽  
Expression Of Genes ◽  
Nuclear Extracts ◽  
And Function ◽  
Peptide Affinity

NFAT5 is an osmoregulated transcription factor that particularly increases expression of genes involved in protection against hypertonicity. Transcription factors often contain unstructured regions that bind co-regulatory proteins that are crucial for their function. The NH2-terminal region of NFAT5 contains regions predicted to be intrinsically disordered. We used peptide aptamer-based affinity chromatography coupled with mass spectrometry to identify protein preys pulled down by one or more overlapping 20 amino acid peptide baits within a predicted NH2-terminal unstructured region of NFAT5. We identify a total of 467 unique protein preys that associate with at least one NH2-terminal peptide bait from NFAT5 in either cytoplasmic or nuclear extracts from HEK293 cells treated with elevated, normal, or reduced NaCl concentrations. Different sets of proteins are pulled down from nuclear vs. cytoplasmic extracts. We used GeneCards to ascertain known functions of the protein preys. The protein preys include many that were previously known, but also many novel ones. Consideration of the novel ones suggests many aspects of NFAT5 regulation, interaction and function that were not previously appreciated, for example, hypertonicity inhibits NFAT5 by sumoylating it and the NFAT5 protein preys include components of the CHTOP complex that desumoylate proteins, an action that should contribute to activation of NFAT5.

scholarly journals PAG-3, a Zn-finger transcription factor, determines neuroblast fate in C. elegans

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1763-1774 ◽  
Author(s):  
Scott Cameron ◽  
Scott G. Clark ◽  
Joan B. McDermott ◽  
Eric Aamodt ◽  
H. Robert Horvitz
Keyword(s):  
Transcription Factor ◽  
Cell Fate ◽  
Daughter Cell ◽  
Cell Lineage ◽  
Blast Cell ◽  
Cell Fates ◽  
Zinc Finger Transcription Factor ◽  
C Elegans ◽  
Mother Cells

During Caenorhabditis elegans development, the patterns of cell divisions, cell fates and programmed cell deaths are reproducible from animal to animal. In a search for mutants with abnormal patterns of programmed cell deaths in the ventral nerve cord, we identified mutations in the gene pag-3, which encodes a zinc-finger transcription factor similar to the mammalian Gfi-1 and Drosophila Senseless proteins. In pag-3 mutants, specific neuroblasts express the pattern of divisions normally associated with their mother cells, producing with each reiteration an abnormal anterior daughter neuroblast and an extra posterior daughter cell that either terminally differentiates or undergoes programmed cell death, which accounts for the extra cell corpses seen in pag-3 mutants. In addition, some neurons do not adopt their normal fates in pag-3 mutants. The phenotype of pag-3 mutants and the expression pattern of the PAG-3 protein suggest that in some lineages pag-3 couples the determination of neuroblast cell fate to subsequent neuronal differentiation. We propose that pag-3 counterparts in other organisms determine blast cell identity and for this reason may lead to cell lineage defects and cell proliferation when mutated.

scholarly journals The transcriptional corepressor CTBP-1 acts with the SOX family transcription factor EGL-13 to maintain AIA interneuron cell identity in C. elegans

2021 ◽  
Author(s):  
Josh Saul ◽  
Takashi Hirose ◽  
Robert Horvitz
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Cell Fate ◽  
Transcriptional Corepressor ◽  
Cell Identity ◽  
C Elegans ◽  
Dna Binding Specificity ◽  
A Cell ◽  
Transcriptional Corepressors ◽  
And Function

Cell identity is characterized by a distinct combination of gene expression, cell morphology and cellular function established as progenitor cells divide and differentiate. Following establishment, cell identities can be unstable and require active and continuous maintenance throughout the remaining life of a cell. Mechanisms underlying the maintenance of cell identities are incompletely understood. Here we show that the gene ctbp-1, which encodes the transcriptional corepressor C-terminal binding protein-1 (CTBP-1), is essential for the maintenance of the identities of the two AIA interneurons in the nematode Caenorhabditis elegans. ctbp-1 is not required for the establishment of the AIA cell fate but rather functions cell-autonomously and can act in older worms to maintain proper AIA gene expression, morphology and function. From a screen for suppressors of the ctbp-1 mutant phenotype, we identified the gene egl-13, which encodes a SOX family transcription factor. We found that egl-13 regulates AIA function and aspects of AIA gene expression, but not AIA morphology. We conclude that the CTBP-1 protein maintains AIA cell identity in part by utilizing EGL-13 to repress transcriptional activity in the AIAs. More generally, we propose that transcriptional corepressors like CTBP-1 might be critical factors in the maintenance of cell identities, harnessing the DNA-binding specificity of transcription factors like EGL-13 to selectively regulate gene expression in a cell-specific manner.

scholarly journals The HLH-6 Transcription Factor Regulates C. elegans Pharyngeal Gland Development and Function

PLoS Genetics ◽  
2008 ◽  
Vol 4 (10) ◽  
pp. e1000222 ◽  
Author(s):  
Ryan B. Smit ◽  
Ralf Schnabel ◽  
Jeb Gaudet
Keyword(s):  
Transcription Factor ◽  
C Elegans ◽  
Pharyngeal Gland ◽  
And Function ◽  
Gland Development

scholarly journals Peptide affinity analysis of proteins that bind to an unstructured region containing the transactivating domain of the osmoprotective transcription factor NFAT5

2016 ◽  
Vol 48 (11) ◽  
pp. 835-849
Author(s):  
Jenna F. Dumond ◽  
Xue Zhang ◽  
Yuichiro Izumi ◽  
Kevin Ramkissoon ◽  
Guanghui Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
The Novel ◽  
Mrna Transcription ◽  
Cell Extracts ◽  
Expression Of Genes ◽  
Nuclear Extracts ◽  
Potential Binding ◽  
Associated Proteins ◽  
And Function ◽  
Peptide Affinity

NFAT5 is a transcription factor originally identified because it is activated by hypertonicity and that activation increases expression of genes that protect against the adverse effects of the hypertonicity. However, its targets also include genes not obviously related to tonicity. The transactivating domain of NFAT5 is contained in its COOH-terminal region, which is predicted to be unstructured. Unstructured regions are common in transcription factors particularly in transactivating domains where they can bind co-regulatory proteins essential to their function. To identify potential binding partners of NFAT5 from either cytoplasmic or nuclear HEK293 cell extracts, we used peptide affinity chromatography followed by mass spectrometry. Peptide aptamer-baits consisted of overlapping 20 amino acid peptides within the predicted COOH-terminal unstructured region of NFAT5. We identify a total of 351 unique protein preys that associate with at least one COOH-terminal peptide bait from NFAT5 in either cytoplasmic or nuclear extracts from cells incubated at various tonicities (NaCl varied). In addition to finding many proteins already known to associate with NFAT5, we found many new ones whose function suggest novel aspects of NFAT5 regulation, interaction, and function. Relatively few of the proteins pulled down by peptide baits from NFAT5 are generally involved in transcription, and most, therefore, are likely to be specifically related to the regulation of NFAT5 or its function. The novel associated proteins are involved with cancer, effects of hypertonicity on chromatin, development, splicing of mRNA, transcription, and vesicle trafficking.

Sign in / Sign up

Export Citation Format

Share Document