Spatially regulated SpEts4 transcription factor activity along the sea urchin embryo animal-vegetal axis

Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1729-1737 ◽  
Author(s):  
Z. Wei ◽  
L.M. Angerer ◽  
R.C. Angerer

Because the transcription of the SpHE gene is regulated cell-autonomously and asymmetrically along the maternally determined animal-vegetal axis of the very early sea urchin embryo, its regulators provide an excellent entry point for investigating the mechanism(s) that establishes this initial polarity. Previous studies support a model in which spatial regulation of SpHE transcription relies on multiple nonvegetal positive transcription factor activities (Wei, Z., Angerer, L. M. and Angerer, R. C. (1997) Dev. Biol. 187, 71–78) and a yeast one-hybrid screen has identified one, SpEts4, which binds with high specificity to a cis element in the SpHE regulatory region and confers positive activation of SpHE promoter transgenes (Wei, Z., Angerer, R. C. and Angerer, L. M. (1999) Mol. Cell. Biol. 19, 1271–1278). Here we demonstrate that SpEts4 can bind to the regulatory region of the endogenous SpHE gene because a dominant repressor, created by fusing SpEts4 DNA binding and Drosophila engrailed repression domains, suppresses its transcription. The pattern of expression of the SpEts4 gene is consistent with a role in regulating SpHE transcription in the nonvegetal region of the embryo during late cleavage/early blastula stages. Although maternal transcripts are uniformly distributed in the egg and early cleaving embryo, they rapidly turn over and are replaced by zygotic transcripts that accumulate in a pattern congruent with SpHE transcription. In addition, in vivo functional tests show that the SpEts4 cis element confers nonvegetal transcription of a beta-galactosidase reporter gene containing the SpHE basal promoter, and provide strong evidence that the activity of this transcription factor is an integral component of the nonvegetal transcriptional regulatory apparatus, which is proximal to, or part of, the mechanism that establishes the animal-vegetal axis of the sea urchin embryo.

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5473-5483 ◽  
Author(s):  
A.P. Kenny ◽  
D. Kozlowski ◽  
D.W. Oleksyn ◽  
L.M. Angerer ◽  
R.C. Angerer

We have identified a Sox family transcription factor, SpSoxB1, that is asymmetrically distributed among blastomeres of the sea urchin embryo during cleavage, beginning at 4th cleavage. SpSoxB1 interacts with a cis element that is essential for transcription of SpAN, a gene that is activated cell autonomously and expressed asymmetrically along the animal-vegetal axis. In vitro translated SpSoxB1 forms a specific complex with this cis element whose mobility is identical to that formed by a protein in nuclear extracts. An anti-SpSoxB1 rabbit polyclonal antiserum specifically supershifts this DNA-protein complex and recognizes a single protein on immunoblots of nuclear proteins that comigrates with in vitro translated SpSoxB1. Developmental immunoblots of total proteins at selected early developmental stages, as well as EMSA of egg and 16-cell stage proteins, show that SpSoxB1 is present at low levels in unfertilized eggs and progressively accumulates during cleavage. SpSoxB1 maternal transcripts are uniformly distributed in the unfertilized egg and the protein accumulates to similar, high concentrations in all nuclei of 4- and 8-cell embryos. However, at fourth cleavage, the micromeres, which are partitioned by asymmetric division of the vegetal 4 blastomeres, have reduced nuclear levels of the protein, while high levels persist in their sister macromeres and in the mesomeres. During cleavage, the uniform maternal SpSoxB1 transcript distribution is replaced by a zygotic nonvegetal pattern that reinforces the asymmetric SpSoxB1 protein distribution and reflects the corresponding domain of SpAN mRNA accumulation at early blastula stage (approximately 150 cells). The vegetal region lacking nuclear SpSoxB1 gradually expands so that, after blastula stage, only cells in differentiating ectoderm accumulate this protein in their nuclei. The results reported here support a model in which SpSoxB1 is a major regulator of the initial phase of asymmetric transcription of SpAN in the nonvegetal domain by virtue of its distribution at 4th cleavage and is subsequently an important spatial determinant of expression in the early blastula. This factor is the earliest known spatially restricted regulator of transcription along the animal-vegetal axis of the sea urchin embryo.


2014 ◽  
Vol 24 (16) ◽  
pp. 3914-3918 ◽  
Author(s):  
Marina N. Semenova ◽  
Dmitry V. Tsyganov ◽  
Oleg R. Malyshev ◽  
Oleg V. Ershov ◽  
Ivan N. Bardasov ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (6) ◽  
pp. 1938-1947 ◽  
Author(s):  
Tomohiko Tamura ◽  
Pratima Thotakura ◽  
Tetsuya S. Tanaka ◽  
Minoru S. H. Ko ◽  
Keiko Ozato

Abstract Interferon regulatory factor-8 (IRF-8)/interferon consensus sequence–binding protein (ICSBP) is a transcription factor that controls myeloid-cell development. Microarray gene expression analysis of Irf-8-/- myeloid progenitor cells expressing an IRF-8/estrogen receptor chimera (which differentiate into macrophages after addition of estradiol) was used to identify 69 genes altered by IRF-8 during early differentiation (62 up-regulated and 7 down-regulated). Among them, 4 lysosomal/endosomal enzyme-related genes (cystatin C, cathepsin C, lysozyme, and prosaposin) did not require de novo protein synthesis for induction, suggesting that they were direct targets of IRF-8. We developed a reporter assay system employing a self-inactivating retrovirus and analyzed the cystatin C and cathepsin C promoters. We found that a unique cis element mediates IRF-8–induced activation of both promoters. Similar elements were also found in other IRF-8 target genes with a consensus sequence (GAAANN[N]GGAA) comprising a core IRF-binding motif and an Ets-binding motif; this sequence is similar but distinct from the previously reported Ets/IRF composite element. Chromatin immunoprecipitation assays demonstrated that IRF-8 and the PU.1 Ets transcription factor bind to this element in vivo. Collectively, these data indicate that IRF-8 stimulates transcription of target genes through a novel cis element to specify macrophage differentiation.


Development ◽  
1993 ◽  
Vol 119 (3) ◽  
pp. 833-840 ◽  
Author(s):  
N. Armstrong ◽  
J. Hardin ◽  
D.R. McClay

In the sea urchin embryo, the primary mesenchyme cells (PMCs) make extensive contact with the ectoderm of the blastula wall. This contact is shown to influence production of the larval skeleton by the PMCs. A previous observation showed that treatment of embryos with NiCl2 can alter spicule number and skeletal pattern (Hardin et al. (1992) Development, 116, 671–685). Here, to explore the tissue sensitivity to NiCl2, experiments recombined normal or NiCl2-treated PMCs with either normal or NiCl2-treated PMC-less host embryos. We find that NiCl2 alters skeleton production by influencing the ectoderm of the blastula wall with which the PMCs interact. The ectoderm is responsible for specifying the number of spicules made by the PMCs. In addition, experiments examining skeleton production in vitro and in half- and quarter-sized embryos shows that cell interactions also influence skeleton size. PMCs grown in vitro away from interactions with the rest of the embryo, can produce larger spicules than in vivo. Thus, the epithelium of the blastula wall appears to provide spatial and scalar information that regulates skeleton production by the PMCs.


Blood ◽  
2004 ◽  
Vol 104 (10) ◽  
pp. 3106-3116 ◽  
Author(s):  
Veronica Valverde-Garduno ◽  
Boris Guyot ◽  
Eduardo Anguita ◽  
Isla Hamlett ◽  
Catherine Porcher ◽  
...  

Abstract Cis-element identification is a prerequisite to understand transcriptional regulation of gene loci. From analysis of a limited number of conserved gene loci, sequence comparison has proved a robust and efficient way to locate cis-elements. Human and mouse GATA1 genes encode a critical hematopoietic transcription factor conserved in expression and function. Proper control of GATA1 transcription is critical in regulating myeloid lineage specification and maturation. Here, we compared sequence and systematically mapped position of DNase I hypersensitive sites, acetylation status of histone H3/H4, and in vivo binding of transcription factors over approximately 120 kilobases flanking the human GATA1 gene and the corresponding region in mice. Despite lying in approximately 10 megabase (Mb) conserved syntenic segment, the chromatin structures of the 2 homologous loci are strikingly different. The 2 previously unidentified hematopoietic cis-elements, one in each species, are not conserved in position and sequence and have enhancer activity in erythroid cells. In vivo, they both bind the transcription factors GATA1, SCL, LMO2, and Ldb1. More broadly, there are both species- and regulatory element–specific patterns of transcription factor binding. These findings suggest that some cis-elements regulating human and mouse GATA1 genes differ. More generally, mouse human sequence comparison may fail to identify all cis-elements.


2002 ◽  
Vol 30 (2) ◽  
pp. 1-9 ◽  
Author(s):  
A. D. Sharrocks

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.


1994 ◽  
Vol 47 (2) ◽  
pp. 165-186 ◽  
Author(s):  
Chiou-Hwa Yuh ◽  
Andrew Ransick ◽  
Pedro Martinez ◽  
Roy J. Britten ◽  
Eric H. Davidson

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