Open Access. Powered by Scholars. Published by Universities.®

Cell and Developmental Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 10 of 10

Full-Text Articles in Cell and Developmental Biology

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang Oct 2015

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang

Victor R. Ambros

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …


The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros Oct 2015

The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros

Victor R. Ambros

Animals developing in the wild encounter a range of environmental conditions, and so developmental mechanisms have evolved that can accommodate different environmental contingencies. Harsh environmental conditions cause Caenorhabditis elegans larvae to arrest as stress-resistant "dauer" larvae after the second larval stage (L2), thereby indefinitely postponing L3 cell fates. HBL-1 is a key transcriptional regulator of L2 vs. L3 cell fate. Through the analysis of genetic interactions between mutations of hbl-1 and of genes encoding regulators of dauer larva formation, we find that hbl-1 can also modulate the dauer formation decision in a complex manner. We propose that dynamic interactions between …


A Laminin 511 Matrix Is Regulated By Taz And Functions As The Ligand For The Alpha6bbeta1 Integrin To Sustain Breast Cancer Stem Cells, Cheng Chang, Hira Lal Goel, Huijie Gao, Bryan M. Pursell, Leonard D. Shultz, Dale L. Greiner, Sulev Ingerpuu, Manuel Patarroyo, Shiliang Cao, Elgene Lim, Junhao Mao, Karen Kulju. Mckee, Peter D. Yurchenco, Arthur M. Mercurio May 2015

A Laminin 511 Matrix Is Regulated By Taz And Functions As The Ligand For The Alpha6bbeta1 Integrin To Sustain Breast Cancer Stem Cells, Cheng Chang, Hira Lal Goel, Huijie Gao, Bryan M. Pursell, Leonard D. Shultz, Dale L. Greiner, Sulev Ingerpuu, Manuel Patarroyo, Shiliang Cao, Elgene Lim, Junhao Mao, Karen Kulju. Mckee, Peter D. Yurchenco, Arthur M. Mercurio

Arthur M. Mercurio

Understanding how the extracellular matrix impacts the function of cancer stem cells (CSCs) is a significant but poorly understood problem. We report that breast CSCs produce a laminin (LM) 511 matrix that promotes self-renewal and tumor initiation by engaging the alpha6Bbeta1 integrin and activating the Hippo transducer TAZ. Although TAZ is important for the function of breast CSCs, the mechanism is unknown. We observed that TAZ regulates the transcription of the alpha5 subunit of LM511 and the formation of a LM511 matrix. These data establish a positive feedback loop involving TAZ and LM511 that contributes to stemness in breast cancer.


The Nuclear Factor Of Activated T Cells (Nfat) Transcription Factor Nfatp (Nfatc2) Is A Repressor Of Chondrogenesis, Ann M. Ranger, Louis C. Gerstenfeld, Jinxi Wang, Tamiyo Kon, Hyunsu Bae, Ellen M. Gravallese, Melvin J. Glimcher, Laurie H. Glimcher Apr 2015

The Nuclear Factor Of Activated T Cells (Nfat) Transcription Factor Nfatp (Nfatc2) Is A Repressor Of Chondrogenesis, Ann M. Ranger, Louis C. Gerstenfeld, Jinxi Wang, Tamiyo Kon, Hyunsu Bae, Ellen M. Gravallese, Melvin J. Glimcher, Laurie H. Glimcher

Ellen M. Gravallese

Nuclear factor of activated T cells (NFAT) transcription factors regulate gene expression in lymphocytes and control cardiac valve formation. Here, we report that NFATp regulates chondrogenesis in the adult animal. In mice lacking NFATp, resident cells in the extraarticular connective tissues spontaneously differentiate to cartilage. These cartilage cells progressively differentiate and the tissue undergoes endochondral ossification, recapitulating the development of endochondral bone. Proliferation of already existing articular cartilage cells also occurs in some older animals. At both sites, neoplastic changes in the cartilage cells occur. Consistent with these data, NFATp expression is regulated in mesenchymal stem cells induced to differentiate …


A Lipopolysaccharide-Induced Dna-Binding Protein For A Class Ii Gene In B Cells Is Distinct From Nf-Kappa B, Ellen M. Gravallese, Mark R. Boothby, Cynthia M. Smas, Laurie H. Glimcher Apr 2015

A Lipopolysaccharide-Induced Dna-Binding Protein For A Class Ii Gene In B Cells Is Distinct From Nf-Kappa B, Ellen M. Gravallese, Mark R. Boothby, Cynthia M. Smas, Laurie H. Glimcher

Ellen M. Gravallese

Class II (Ia) major histocompatibility complex molecules are cell surface proteins normally expressed by a limited subset of cells of the immune system. These molecules regulate the activation of T cells and are required for the presentation of antigens and the initiation of immune responses. The expression of Ia in B cells is determined by both the developmental stage of the B cell and by certain external stimuli. It has been demonstrated previously that treatment of B cells with lipopolysaccharide (LPS) results in increased surface expression of Ia protein. However, we have confirmed that LPS treatment results in a significant …


Novel Developmental Biology-Based Protocol Of Embryonic Stem Cell Differentiation To Morphologically Sound And Functional Yet Immature Hepatocytes, Terence Bukong, Tracie Lo, Gyongyi Szabo, Angela Dolganiuc Oct 2012

Novel Developmental Biology-Based Protocol Of Embryonic Stem Cell Differentiation To Morphologically Sound And Functional Yet Immature Hepatocytes, Terence Bukong, Tracie Lo, Gyongyi Szabo, Angela Dolganiuc

Gyongyi Szabo

BACKGROUND/AIMS: Liver diseases are common in the United States and often require liver transplantation; however, donated organs are limited and thus alternative sources for liver cells are in high demand. Embryonic stem cells (ESC) can provide a continuous and readily available source of liver cells. ESC differentiation to liver cells is yet to be fully understood and comprehensive differentiation protocols are yet to be defined. Here, we aimed to achieve human (h)ESC differentiation into mature hepatocytes using defined recombinant differentiation factors and metabolites. METHODS: Embryonic stem cell H1 line was sub-cultured on feeder layer. We induced hESCs into endodermal differentiation …


Glycogen Synthase Kinase-3 Is An Endogenous Inhibitor Of Snail Transcription: Implications For The Epithelial-Mesenchymal Transition, Robin E. Bachelder, Sang-Oh Yoon, Clara Franci, Antonio Garcia De Herreros, Arthur M. Mercurio Nov 2010

Glycogen Synthase Kinase-3 Is An Endogenous Inhibitor Of Snail Transcription: Implications For The Epithelial-Mesenchymal Transition, Robin E. Bachelder, Sang-Oh Yoon, Clara Franci, Antonio Garcia De Herreros, Arthur M. Mercurio

Arthur M. Mercurio

We report that the activity of glycogen synthase kinase-3 (GSK-3) is necessary for the maintenance of the epithelial architecture. Pharmacological inhibition of its activity or reducing its expression using small interfering RNAs in normal breast and skin epithelial cells results in a reduction of E-cadherin expression and a more mesenchymal morphology, both of which are features associated with an epithelial-mesenchymal transition (EMT). Importantly, GSK-3 inhibition also stimulates the transcription of Snail, a repressor of E-cadherin and an inducer of the EMT. We identify NFkappaB as a transcription factor inhibited by GSK-3 in epithelial cells that is relevant for Snail expression. …


Supervillin Modulation Of Focal Adhesions Involving Trip6/Zrp-1, Norio Takizawa, Tara C. Smith, Thomas Nebl, Jessica Lynn Crowley, Stephen J. Palmieri, Lawrence M. Lifshitz, Anka G. Ehrhardt, Laura M. Hoffman, Mary C. Beckerle, Elizabeth J. Luna Mar 2008

Supervillin Modulation Of Focal Adhesions Involving Trip6/Zrp-1, Norio Takizawa, Tara C. Smith, Thomas Nebl, Jessica Lynn Crowley, Stephen J. Palmieri, Lawrence M. Lifshitz, Anka G. Ehrhardt, Laura M. Hoffman, Mary C. Beckerle, Elizabeth J. Luna

Elizabeth J. Luna

Cell-substrate contacts, called focal adhesions (FAs), are dynamic in rapidly moving cells. We show that supervillin (SV)--a peripheral membrane protein that binds myosin II and F-actin in such cells--negatively regulates stress fibers, FAs, and cell-substrate adhesion. The major FA regulatory sequence within SV (SV342-571) binds to the LIM domains of two proteins in the zyxin family, thyroid receptor-interacting protein 6 (TRIP6) and lipoma-preferred partner (LPP), but not to zyxin itself. SV and TRIP6 colocalize within large FAs, where TRIP6 may help recruit SV. RNAi-mediated decreases in either protein increase cell adhesion to fibronectin. TRIP6 partially rescues SV effects on stress …


The Lin-41 Rbcc Gene Acts In The C. Elegans Heterochronic Pathway Between The Let-7 Regulatory Rna And The Lin-29 Transcription Factor, Frank Slack, Michael Basson, Zhongchi Liu, Victor Ambros, H. Horvitz, Gary Ruvkun Mar 2000

The Lin-41 Rbcc Gene Acts In The C. Elegans Heterochronic Pathway Between The Let-7 Regulatory Rna And The Lin-29 Transcription Factor, Frank Slack, Michael Basson, Zhongchi Liu, Victor Ambros, H. Horvitz, Gary Ruvkun

Victor R. Ambros

Null mutations in the C. elegans heterochronic gene lin-41 cause precocious expression of adult fates at larval stages. Increased lin-41 activity causes the opposite phenotype, reiteration of larval fates. let-7 mutations cause similar reiterated heterochronic phenotypes that are suppressed by lin-41 mutations, showing that lin-41 is negatively regulated by let-7. lin-41 negatively regulates the timing of LIN-29 adult specification transcription factor expression. lin-41 encodes an RBCC protein, and two elements in the lin-413'UTR are complementary to the 21 nucleotide let-7 regulatory RNA. A lin-41::GFP fusion gene is downregulated in the tissues affected by lin-41 at the time that the let-7 …


The Heterochronic Gene Lin-29 Encodes A Zinc Finger Protein That Controls A Terminal Differentiation Event In Caenorhabditis Elegans, Ann Rougvie, Victor Ambros Jul 1995

The Heterochronic Gene Lin-29 Encodes A Zinc Finger Protein That Controls A Terminal Differentiation Event In Caenorhabditis Elegans, Ann Rougvie, Victor Ambros

Victor R. Ambros

A hierarchy of heterochronic genes, lin-4, lin-14, lin-28 and lin-29, temporally restricts terminal differentiation of Caenorhabditis elegans hypodermal seam cells to the final molt. This terminal differentiation event involves cell cycle exit, cell fusion and the differential regulation of genes expressed in the larval versus adult hypodermis. lin-29 is the most downstream gene in the developmental timing pathway and thus it is the most direct known regulator of these diverse processes. We show that lin-29 encodes a protein with five zinc fingers of the (Cys)2-(His)2 class and thus likely controls these processes by regulating transcription in a stage-specific manner. Consistent …