The developmental switch in embryonic rho-globin expression is correlated with erythroid lineage-specific differences in transcription factor levels

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 1149-1164 ◽  
Author(s):  
M.E. Minie ◽  
T. Kimura ◽  
G. Felsenfeld
Keyword(s):  
Transcription Factor ◽  
Developmental Stages ◽  
Globin Gene ◽  
Strongly Correlated ◽  
Binding Studies ◽  
Specific Expression ◽  
Dna Binding Studies ◽  
Translational Start ◽  
Erythroid Development ◽  
Early Developmental

During chicken embryogenesis, the rho-globin gene is expressed only in the early developmental stages. We have examined the mechanisms that are responsible for this behavior. The transcription of the rho-globin gene is strongly correlated with the presence during development of primitive erythroid lineage cells, consistent with the idea that the expression of the rho-globin gene is restricted to that lineage. The “switching off” of rho-globin during development thus reflects the change from primitive to definitive cell lineages which occurs during erythropoiesis in chicken. We use transient expression assays in primary erythroid and other cells to show that the information for lineage- and tissue-specific expression of the rho-globin gene is contained in a 456 bp region upstream of the gene's translational start site. DNA-binding studies, coupled with analysis of the effect on expression of deletions and binding site mutations, were used to identify important control elements within this 456 bp region. We find that binding sites for the ubiquitous transcription factor Sp1, and the specific hematopoietic factor GATA-1, are crucial for expression of the gene in primitive erythroid cells. Quantitative analysis shows that nuclei of the primitive erythroid lineage contain 10-fold more of these factors than do the nuclei of definitive cells. We show that in principle these differences in factor concentration are sufficient to explain the lineage-specific behavior that we observe in our assays. We suggest that this may be an important part of the mechanism for lineage-restricted rho-globin expression during chicken erythroid development. Similar mechanisms may be involved in regulation of other (but not all) members of the globin family.

scholarly journals Differential regulation of the N-myc gene in transfected cells and transgenic mice.

1990 ◽  
Vol 10 (5) ◽  
pp. 2096-2103 ◽  
Author(s):  
K Zimmerman ◽  
E Legouy ◽  
V Stewart ◽  
R Depinho ◽  
F W Alt
Keyword(s):  
Transgenic Mice ◽  
Developmental Stages ◽  
Specific Expression ◽  
Endogenous Gene ◽  
Numerous Cell ◽  
Transgenic Lines ◽  
Myc Gene ◽  
Early Developmental

The N-myc gene is expressed specifically in the early developmental stages of numerous cell lineages. To assay for sequences that could potentially regulate N-myc expression, we transfected constructs that contained murine N-myc genomic sequences linked to a reporter gene and genomic clones that contained the complete human or murine N-myc genes into cell lines that either express or do not express the endogenous N-myc gene. Following either transient or stable transfection, the introduced N-myc sequences were expressed regardless of the expression status of the endogenous gene. In contrast, when the clones containing the complete human N-myc gene were introduced into the germline of transgenic mice, expression in some transgenic lines paralleled the tissue- and stage-specific expression of the endogenous murine gene. These findings demonstrate differences in the regulation of N-myc genes in recipient cells following in vitro versus in vivo introduction, suggesting that early developmental events may play a role in the regulation of N-myc expression.

scholarly journals An alternative splicing event in the Pax-3 paired domain identifies the linker region as a key determinant of paired domain DNA-binding activity.

1996 ◽  
Vol 16 (12) ◽  
pp. 6677-6686 ◽  
Author(s):  
K J Vogan ◽  
D A Underhill ◽  
P Gros
Keyword(s):  
Alternative Splicing ◽  
Dna Binding ◽  
Developmental Stages ◽  
Paired Domain ◽  
Binding Studies ◽  
Recognition Sequence ◽  
Linker Region ◽  
Glutamine Residue ◽  
Dna Binding Studies

We have identified alternatively spliced isoforms of murine Pax-3 and Pax-7 which differ by the presence or absence of a single glutamine residue in a linker region which separates two distinct DNA-binding subdomains within the paired domain. By reverse transcription-PCR, these isoforms of Pax-3 and Pax-7 (Q+ and Q-) were detected at similar levels through multiple developmental stages in the early mouse embryo. DNA-binding studies using the Q+ and Q- isoforms of Pax-3 revealed that this alternative splicing event had no major effect on the ability of these isoforms to bind to an oligonucleotide specific for the Pax-3 homeodomain (P2) or to a paired domain recognition sequence (e5) that interacts primarily with the N-terminal subdomain of the paired domain. However, DNA-binding studies with sequences (P6CON and CD19-2/A) containing consensus elements for both the N-terminal and C-terminal subdomains revealed that the Q- isoform binds to these sequences with a two- to fivefold-higher affinity; further mutation of the GTCAC core N-terminal subdomain recognition motif of CD19-2/A generated binding sites with a high degree of specificity for the Q- isoform. These differences in DNA binding in vitro were also reflected in the enhanced ability of the Q- isoform to stimulate transcription of a reporter containing multiple copies of CD19-2/A upstream of the thymidine kinase basal promoter. In support of the observations made with these naturally occurring Pax-3 isoforms, introducing a glutamine residue at the analogous position in PAX6 caused a fivefold reduction in binding to P6CON and a complete loss of binding to CD19-2/A and to the C-terminal subdomain-specific probe 5aCON. These studies therefore provide direct evidence for a role for the paired-domain linker region in DNA target site selection, and they identify novel isoforms of Pax-3 and Pax-7 that have the potential to mediate distinct functions in the developing embryo.

scholarly journals Activation mechanism of the multifunctional transcription factor repressor-activator protein 1 (Rap1p).

1996 ◽  
Vol 16 (6) ◽  
pp. 3187-3196 ◽  
Author(s):  
C M Drazinic ◽  
J B Smerage ◽  
M C López ◽  
H V Baker
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Sites ◽  
Glycolytic Enzyme ◽  
Model Systems ◽  
Binding Studies ◽  
Dna Binding Studies ◽  
Combinatorial Interactions ◽  
Uas Element

Transcriptional activation in eukaryotic organisms normally requires combinatorial interactions of multiple transcription factors. In most cases, the precise role played by each transcription factor is not known. The upstream activating sequence (UAS) elements of glycolytic enzyme genes in Saccharomyces cerevisiae are excellent model systems for the study of combinatorial interactions. The yeast protein known as Rap1p acts as both a transcriptional repressor and an activator, depending on sequence context. Rap1p-binding sites are found adjacent to Gcr1p-binding sites in the UAS elements of glycolytic enzyme genes. These UAS elements constitute some of the strongest activating sequences known in S. cerevisiae. In this study, we have investigated the relationship between Rap1p- and Gcr1p-binding sites and the proteins that bind them. In vivo DNA-binding studies with rap1ts mutant strains demonstrated that the inability of Rap1p to bind at its site resulted in the inability of Gcr1p to bind at adjacent binding sites. Synthetic oligonucleotides, modeled on the UAS element of PYK1, in which the relative positions of the Rap1p- and Gcr1p-binding sites were varied prepared and tested for their ability to function as UAS elements. The ability of the oligonucleotides to function as UAS elements was dependent not only on the presence of both binding sites but also on the relative distance between the binding sites. In vivo DNA-binding studies showed that the ability of Rap1p bind its site was independent of Gcr1p but that the ability of Gcr1p to bind its site was dependent on the presence of an appropriately spaced and bound Rap1p-binding site. In vitro binding studies showed Rap1p-enhanced binding of Gcr1p on oligonucleotides modeled after the native PYK1 UAS element but not when the Rap1p- and Gcr1p-binding sites were displaced by 5 nucleotides. This work demonstrates that the role of the Rap1p in the activation of glycolytic enzyme genes is to bind in their UAS elements and to facilitate the binding of Gcr1p at adjacent binding sites.

scholarly journals Hemin enhances the in vitro growth of primitive erythroid progenitor cells

Blood ◽  
1982 ◽  
Vol 60 (2) ◽  
pp. 527-530
Author(s):  
FC Monette ◽  
SA Holden
Keyword(s):  
Progenitor Cells ◽  
Developmental Stages ◽  
In Vitro Growth ◽  
Erythroid Progenitor ◽  
Erythroid Progenitor Cells ◽  
Specific Enhancement ◽  
Erythroid Development ◽  
Early Developmental ◽  
Number Of Cells

Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of “burst-promoting activity.” In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells.

scholarly journals Hemin enhances the in vitro growth of primitive erythroid progenitor cells

Blood ◽  
1982 ◽  
Vol 60 (2) ◽  
pp. 527-530 ◽  
Author(s):  
FC Monette ◽  
SA Holden
Keyword(s):  
Progenitor Cells ◽  
Developmental Stages ◽  
In Vitro Growth ◽  
Erythroid Progenitor ◽  
Erythroid Progenitor Cells ◽  
Specific Enhancement ◽  
Erythroid Development ◽  
Early Developmental ◽  
Number Of Cells

Abstract Since exogenous hemin has been shown to exert a variety of stimulatory effects on erythroid cells, including the augmentation of hemoglobin synthesis, we determined its effect on early stages of erythroid development by employing clonal cells assays. The addition of hemin at a concentration of 2 X 10(-4) M to cultures of normal murine marrow substantially increased the observed number of primitive BFU-E, which was in contrast to its lack of an effect on more mature erythroid colony-forming cells. This cell-specific enhancement of primitive BFU-E resulted in marrow frequencies equivalent to or exceeding those reported in the presence of “burst-promoting activity.” In the presence of hemin, the number of BFU-E was also observed to be linearly related to the number of cells plated at very low plating densities, and the cell titration curve was observed to extrapolate to the origin. The evidence suggests that hemin may be a primary growth regulator of early developmental stages of erythroid progenitor cells.

Differential regulation of the N-myc gene in transfected cells and transgenic mice

1990 ◽  
Vol 10 (5) ◽  
pp. 2096-2103
Author(s):  
K Zimmerman ◽  
E Legouy ◽  
V Stewart ◽  
R Depinho ◽  
F W Alt
Keyword(s):  
Transgenic Mice ◽  
Developmental Stages ◽  
Specific Expression ◽  
Endogenous Gene ◽  
Numerous Cell ◽  
Transgenic Lines ◽  
Myc Gene ◽  
Early Developmental

The N-myc gene is expressed specifically in the early developmental stages of numerous cell lineages. To assay for sequences that could potentially regulate N-myc expression, we transfected constructs that contained murine N-myc genomic sequences linked to a reporter gene and genomic clones that contained the complete human or murine N-myc genes into cell lines that either express or do not express the endogenous N-myc gene. Following either transient or stable transfection, the introduced N-myc sequences were expressed regardless of the expression status of the endogenous gene. In contrast, when the clones containing the complete human N-myc gene were introduced into the germline of transgenic mice, expression in some transgenic lines paralleled the tissue- and stage-specific expression of the endogenous murine gene. These findings demonstrate differences in the regulation of N-myc genes in recipient cells following in vitro versus in vivo introduction, suggesting that early developmental events may play a role in the regulation of N-myc expression.

Mir-144 selectively regulates embryonic α-hemoglobin synthesis during primitive erythropoiesis

Blood ◽  
2009 ◽  
Vol 113 (6) ◽  
pp. 1340-1349 ◽  
Author(s):  
Yan-Fang Fu ◽  
Ting-Ting Du ◽  
Mei Dong ◽  
Kang-Yong Zhu ◽  
Chang-Bin Jing ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Control ◽  
Developmental Stages ◽  
Globin Gene ◽  
Globin Genes ◽  
Specific Expression ◽  
Microrna Gene ◽  
Acting Mechanism ◽  
Globin Gene Regulation ◽  
Primitive Erythropoiesis

Abstract Precise transcriptional control of developmental stage-specific expression and switching of α- and β-globin genes is significantly important to understand the general principles controlling gene expression and the pathogenesis of thalassemia. Although transcription factors regulating β-globin genes have been identified, little is known about the microRNAs and trans-acting mechanism controlling α-globin genes transcription. Here, we show that an erythroid lineage-specific microRNA gene, miR-144, expressed at specific developmental stages during zebrafish embryogenesis, negatively regulates the embryonic α-globin, but not embryonic β-globin, gene expression, through physiologically targeting klfd, an erythroid-specific Krüppel-like transcription factor. Klfd selectively binds to the CACCC boxes in the promoters of both α-globin and miR-144 genes to activate their transcriptions, thus forming a negative feedback circuitry to fine-tune the expression of embryonic α-globin gene. The selective effect of the miR-144-Klfd pathway on globin gene regulation may thereby constitute a novel therapeutic target for improving the clinical outcome of patients with thalassemia.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

Towards understanding the mechanism of action of mithramycin and its analogues: dimerization and DNA binding studies

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
S Weidenbach ◽  
C Hou ◽  
JM Chen ◽  
OV Tsodikov ◽  
J Rohr
Keyword(s):  
Dna Binding ◽  
Mechanism Of Action ◽  
Binding Studies ◽  
Dna Binding Studies

Review of early developmental stages of trilobites and agnostids from the Barrandian area (Czech Republic)

2017 ◽  
Vol 186 (1) ◽  
pp. 103-112
Author(s):  
Lukáš Laibl ◽  
Oldřich Fatka
Keyword(s):  
Czech Republic ◽  
Developmental Stages ◽  
History Of Research ◽  
Early Developmental Stages ◽  
History Of ◽  
Barrandian Area ◽  
Early Developmental

This contribution briefly summarizes the history of research, modes of preservation and stratigraphic distribution of 51 trilobite and five agnostid taxa from the Barrandian area, for which the early developmental stages have been described.

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