scholarly journals Specification of cell fate in the sea urchin embryo: summary and some proposed mechanisms

Development ◽  
1998 ◽  
Vol 125 (17) ◽  
pp. 3269-3290 ◽  
Author(s):  
E.H. Davidson ◽  
R.A. Cameron ◽  
A. Ransick
Keyword(s):  
Cell Fate ◽  
Sea Urchin ◽  
Cell Types ◽  
Expression Of Genes ◽  
Sea Urchin Embryo ◽  
Indirect Development ◽  
Genes Encoding ◽  
Stage Embryo ◽  
Gene Regulatory ◽  
Signaling Interactions

An early set of blastomere specifications occurs during cleavage in the sea urchin embryo, the result of both conditional and autonomous processes, as proposed in the model for this embryo set forth in 1989. Recent experimental results have greatly illuminated the mechanisms of specification in some early embryonic territories, though others remain obscure. We review the progressive process of specification within given lineage elements, and with reference to the early axial organization of the embryo. Evidence for the conditional specification of the veg2 lineage subelement of the endoderm and other potential interblastomere signaling interactions in the cleavage-stage embryo are summarized. Definitive boundaries between mesoderm and endoderm territories of the vegetal plate, and between endoderm and overlying ectoderm, are not established until later in development. These processes have been clarified by numerous observations on spatial expression of various genes, and by elegant lineage labeling studies. The early specification events depend on regional mobilization of maternal regulatory factors resulting at once in the zygotic expression of genes encoding transcription factors, as well as downstream genes encoding proteins characteristic of the cell types that will much later arise from the progeny of the specified blastomeres. This embryo displays a maximal form of indirect development. The gene regulatory network underlying the embryonic development reflects the relative simplicity of the completed larva and of the processes required for its formation. The requirements for postembryonic adult body plan formation in the larval rudiment include engagement of a new level of genetic regulatory apparatus, exemplified by the Hox gene complex.

scholarly journals Encoding regulatory state boundaries in the pregastrular oral ectoderm of the sea urchin embryo

2014 ◽  
Vol 111 (10) ◽  
pp. E906-E913 ◽  
Author(s):  
Enhu Li ◽  
Miao Cui ◽  
Isabelle S. Peter ◽  
Eric H. Davidson
Keyword(s):  
Spatial Pattern ◽  
Sea Urchin ◽  
Regulatory Network ◽  
Regulatory State ◽  
Apical Plate ◽  
Sea Urchin Embryo ◽  
Oral Ectoderm ◽  
Positive Regulators ◽  
Gene Regulatory ◽  
Per Se

By gastrulation the ectodermal territories of the sea urchin embryo have developed an unexpectedly complex spatial pattern of sharply bounded regulatory states, organized orthogonally with respect to the animal/vegetal and oral/aboral axes of the embryo. Although much is known of the gene regulatory network (GRN) linkages that generate these regulatory states, the principles by which the boundaries between them are positioned and maintained have remained undiscovered. Here we determine the encoded genomic logic responsible for the boundaries of the oral aspect of the embryo that separate endoderm from ectoderm and ectoderm from neurogenic apical plate and that delineate the several further subdivisions into which the oral ectoderm per se is partitioned. Comprehensive regulatory state maps, including all spatially expressed oral ectoderm regulatory genes, were established. The circuitry at each boundary deploys specific repressors of regulatory states across the boundary, identified in this work, plus activation by broadly expressed positive regulators. These network linkages are integrated with previously established interactions on the oral/aboral axis to generate a GRN model encompassing the 2D organization of the regulatory state pattern in the pregastrular oral ectoderm of the embryo.

Abstract 191: Transcriptional Regulation of Renin by Nuclear Receptors Co-regulated With Renin

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Ko-Ting Lu ◽  
Eric T Weatherford ◽  
Pimonrat Ketsawatsomkron ◽  
Justin L Grobe ◽  
Curt D Sigmund
Keyword(s):  
Gene Expression ◽  
Nuclear Receptors ◽  
Estrogen Receptor Alpha ◽  
Hormone Receptors ◽  
Cell Types ◽  
Negative Control ◽  
Sirna Duplex ◽  
Expression Of Genes ◽  
Renin Gene ◽  
Genes Encoding

Expression of the renin gene is required to maintain normal morphological and physiological identity of renal juxtaglomerular (JG) cells, yet the mechanisms regulating renin gene transcription remain elusive. We re-examined data from Brunskill et. al (JASN 22:2213, 2011), investigating genome-wide gene expression in JG and other renal cell types. Based on our previous data implicating nuclear receptors (RAR, RXR, VDR, PPARG, Nr2f2 and Nr2f6) in the regulation of mouse and human renin gene expression, we focused our analysis on the expression of genes encoding the 48 nuclear hormone receptors and their co-regulation with renin. Several nuclear receptors have an expression pattern emulating that of renin, that is, they were similarly enriched in JG cells but not in other cell types. These include Esr1, Nr1h4, Ppara, VDR, Nr1i2, Ppard, Hnf4g, Nr1h3, Thrb, Hnf4a, Esrrg, Nr4a3, Nr3c2, and Ar. We tested the hypothesis that a nuclear receptor that is co-regulated with renin may participate in renin gene regulation. To accomplish this, endogenous renin expression was evaluated in renin-expressing As4.1 cells after siRNA-mediated knock down of selected nuclear receptors. Each experiment included a negative control siRNA duplex (NC) that does not target any known genes. By way of example, siRNA-mediated inhibition of estrogen receptor alpha (Esr1) by 70-80% resulted in a 2-fold decrease in renin mRNA (fold change ± SEM: siEsr1: 0.4±0.2, p<0.001 vs NC). Similar results were obtained with a different siRNA targeting Esr1. Interestingly, loss of Esr1 also caused up-regulation of vitamin D receptor (VDR, 2.8±0.7 fold, p<0.001 vs NC) and Nr2f6 (2.0±0.2 fold, p<0.05 vs NC), both of which are known to be negative regulators of renin. Similarly, both renin (0.1±0.02, p<0.001 vs untreated) and Esr1 (0.3±0.1, p<0.05 vs untreated) mRNA were reduced in the kidney from mice treated with deoxycorticosterone acetate (50mg) and receiving 0.15 M NaCl in drinking water for 21 days (DOCA-salt). These data suggest Esr1 may regulate renin expression. Studies are in progress to assess if Esr1 stimulates renin expression on its own or acts by affecting the level of other nuclear receptors; and to determine if other co-regulated nuclear receptors also regulate expression of the renin gene.

scholarly journals Activation of the skeletogenic gene regulatory network in the early sea urchin embryo

Development ◽  
2010 ◽  
Vol 137 (7) ◽  
pp. 1149-1157 ◽  
Author(s):  
T. Sharma ◽  
C. A. Ettensohn
Keyword(s):  
Gene Regulatory Network ◽  
Sea Urchin ◽  
Regulatory Network ◽  
Sea Urchin Embryo ◽  
Gene Regulatory

scholarly journals Specific functions of the Wnt signaling system in gene regulatory networks throughout the early sea urchin embryo

2014 ◽  
Vol 111 (47) ◽  
pp. E5029-E5038 ◽  
Author(s):  
Miao Cui ◽  
Natnaree Siriwon ◽  
Enhu Li ◽  
Eric H. Davidson ◽  
Isabelle S. Peter
Keyword(s):  
Wnt Signaling ◽  
Sea Urchin ◽  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Signaling System ◽  
Sea Urchin Embryo ◽  
Gene Regulatory

scholarly journals Using CRISPR to understand and manipulate gene regulation

Development ◽  
2021 ◽  
Vol 148 (9) ◽  
Author(s):  
Ersin Akinci ◽  
Marisa C. Hamilton ◽  
Benyapa Khowpinitchai ◽  
Richard I. Sherwood
Keyword(s):  
Gene Regulation ◽  
Cell Fate ◽  
Disease Modeling ◽  
Cell Types ◽  
Future Application ◽  
Gene Dysregulation ◽  
Epigenetic Code ◽  
Gene Regulatory ◽  
Correct Level ◽  
Biology Research

ABSTRACT Understanding how genes are expressed in the correct cell types and at the correct level is a key goal of developmental biology research. Gene regulation has traditionally been approached largely through observational methods, whereas perturbational approaches have lacked precision. CRISPR-Cas9 has begun to transform the study of gene regulation, allowing for precise manipulation of genomic sequences, epigenetic functionalization and gene expression. CRISPR-Cas9 technology has already led to the discovery of new paradigms in gene regulation and, as new CRISPR-based tools and methods continue to be developed, promises to transform our knowledge of the gene regulatory code and our ability to manipulate cell fate. Here, we discuss the current and future application of the emerging CRISPR toolbox toward predicting gene regulatory network behavior, improving stem cell disease modeling, dissecting the epigenetic code, reprogramming cell fate and treating diseases of gene dysregulation.

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