scholarly journals The ubiquitous octamer-binding protein(s) is sufficient for transcription of immunoglobulin genes.

1990 ◽  
Vol 10 (3) ◽  
pp. 982-990 ◽  
Author(s):  
D G Johnson ◽  
L Carayannopoulos ◽  
J D Capra ◽  
P W Tucker ◽  
J H Hanke

All immunoglobulin genes contain a conserved octanucleotide promoter element, ATGCAAAT, which has been shown to be required for their normal B-cell-specific transcription. Proteins that bind this octamer have been purified, and cDNAs encoding octamer-binding proteins have been cloned. Some of these proteins (referred to as OTF-2) are lymphoid specific, whereas at least one other, and possibly more (referred to as OTF-1), is found ubiquitously in all cell types. The exact role of these different proteins in directing the tissue-specific expression of immunoglobulin genes is unclear. We have identified two human pre-B-cell lines that contain extremely low levels of OTF-2 yet still express high levels of steady-state immunoglobulin heavy-chain mRNA in vivo and efficiently transcribe an immunoglobulin gene in vitro. Addition of a highly enriched preparation of OTF-1 made from one of these pre-B cells or from HeLa cells specifically stimulated in vitro transcription of an immunoglobulin gene. Furthermore, OFT-1 appeared to have approximately the same transactivation ability as OTF-2 when normalized for binding activity. These results suggest that OTF-1, without OTF-2, is sufficient for transcription of immunoglobulin genes and that OTF-2 alone is not responsible for the B-cell-specific regulation of immunoglobulin gene expression.

1990 ◽  
Vol 10 (3) ◽  
pp. 982-990
Author(s):  
D G Johnson ◽  
L Carayannopoulos ◽  
J D Capra ◽  
P W Tucker ◽  
J H Hanke

All immunoglobulin genes contain a conserved octanucleotide promoter element, ATGCAAAT, which has been shown to be required for their normal B-cell-specific transcription. Proteins that bind this octamer have been purified, and cDNAs encoding octamer-binding proteins have been cloned. Some of these proteins (referred to as OTF-2) are lymphoid specific, whereas at least one other, and possibly more (referred to as OTF-1), is found ubiquitously in all cell types. The exact role of these different proteins in directing the tissue-specific expression of immunoglobulin genes is unclear. We have identified two human pre-B-cell lines that contain extremely low levels of OTF-2 yet still express high levels of steady-state immunoglobulin heavy-chain mRNA in vivo and efficiently transcribe an immunoglobulin gene in vitro. Addition of a highly enriched preparation of OTF-1 made from one of these pre-B cells or from HeLa cells specifically stimulated in vitro transcription of an immunoglobulin gene. Furthermore, OFT-1 appeared to have approximately the same transactivation ability as OTF-2 when normalized for binding activity. These results suggest that OTF-1, without OTF-2, is sufficient for transcription of immunoglobulin genes and that OTF-2 alone is not responsible for the B-cell-specific regulation of immunoglobulin gene expression.


1987 ◽  
Vol 7 (5) ◽  
pp. 1989-1994 ◽  
Author(s):  
R Sen ◽  
D Baltimore

Transfection experiments have led to the identification of three DNA sequences that are responsible for the tissue-specific expression of immunoglobulin genes. As a first step toward characterizing these regulatory phenomena at the biochemical level, we report the development of an in vitro transcription system from cells of the B lymphoid lineage. In these extracts, transcription of the MOPC41 kappa promoter is correctly initiated and dependent on the presence of an upstream sequence element located between -44 and -79 base pairs from the cap site. Second, although standard in vitro transcriptions are not affected by the presence or absence of enhancer sequences, we observed that the addition of polyethylene glycol led to a B-cell extract-specific suppression of transcription from a template that carries an immunoglobulin enhancer.


1987 ◽  
Vol 7 (5) ◽  
pp. 1989-1994
Author(s):  
R Sen ◽  
D Baltimore

Transfection experiments have led to the identification of three DNA sequences that are responsible for the tissue-specific expression of immunoglobulin genes. As a first step toward characterizing these regulatory phenomena at the biochemical level, we report the development of an in vitro transcription system from cells of the B lymphoid lineage. In these extracts, transcription of the MOPC41 kappa promoter is correctly initiated and dependent on the presence of an upstream sequence element located between -44 and -79 base pairs from the cap site. Second, although standard in vitro transcriptions are not affected by the presence or absence of enhancer sequences, we observed that the addition of polyethylene glycol led to a B-cell extract-specific suppression of transcription from a template that carries an immunoglobulin enhancer.


Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 649-656 ◽  
Author(s):  
K. Fechtel ◽  
D.K. Fristrom ◽  
J.W. Fristrom

The components of the pupal cuticle are the main differentiation products synthesized by both the larval and adult epidermis during the prepupal period of Drosophila development. The pupal cuticle is formed in vitro by imaginal discs in response to a 6 h pulse of 20-hydroxyecdysone (20-HE). We previously described the isolation and initial characterization of four ecdysone-dependent genes (EDGs) whose expression in imaginal discs occurs only in response to a pulse of 20-HE. In this report, we demonstrate that the pattern of temporal and tissue-specific expression of these EDGs in vivo is like that expected for genes that encode pupal cuticle proteins. Transcripts of these genes are detected in prepupae only in the epidermis and only when cuticle components are synthesized and secreted. Nonetheless, their temporal and spatial patterns of accumulation differ. EDG-84A-1 transcripts accumulate only in prepupae and only in imaginal cells. EDG-78E and EDG-64CD transcripts accumulate at the same time in both larval and imaginal cells. EDG42-A transcripts appear first in prepupae in imaginal cells and then, after a 2–4 h lag, in larval cells. It is evident that some genes are not restricted in their expression to only larval or imaginal epidermis.


2018 ◽  
Vol 115 (25) ◽  
pp. E5736-E5745 ◽  
Author(s):  
Yaara Tabib ◽  
Nora S. Jaber ◽  
Maria Nassar ◽  
Tal Capucha ◽  
Gabriel Mizraji ◽  
...  

AXL, a member of the TYRO3, AXL, and MERTK (TAM) receptor tyrosine kinase family, has been shown to play a role in the differentiation and activation of epidermal Langerhans cells (LCs). Here, we demonstrate that growth arrest-specific 6 (GAS6) protein, the predominant ligand of AXL, has no impact on LC differentiation and homeostasis. We thus examined the role of protein S (PROS1), the other TAM ligand acting primarily via TYRO3 and MERTK, in LC function. Genetic ablation of PROS1 in keratinocytes resulted in a typical postnatal differentiation of LCs; however, a significant reduction in LC frequencies was observed in adult mice due to increased apoptosis. This was attributed to altered expression of cytokines involved in LC development and tissue homeostasis within keratinocytes. PROS1 was then excised in LysM+ cells to target LCs at early embryonic developmental stages, as well as in adult monocytes that also give rise to LCs. Differentiation and homeostasis of LCs derived from embryonic precursors was not affected following Pros1 ablation. However, differentiation of LCs from bone marrow (BM) precursors in vitro was accelerated, as was their capability to reconstitute epidermal LCs in vivo. These reveal an inhibitory role for PROS1 on BM-derived LCs. Collectively, this study highlights a cell-specific regulation of LC differentiation and homeostasis by TAM signaling.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Virginia J. Savin ◽  
Mukut Sharma ◽  
Jianping Zhou ◽  
David Gennochi ◽  
Timothy Fields ◽  
...  

CLCF-1 is a cytokine known for B-cell stimulation and for neurotrophic properties. We have identified CLCF-1 as a potential injurious factor in the human renal disease focal segmental glomerulosclerosis (FSGS). We investigated its effects on renal cells and renal function inin vitroandin vivostudies. Methods include measurement of the effect of CLCF-1 on phosphorylation of target molecules of the JAK/STAT pathway, on cytoskeleton and cell morphology in cultured podocytes, on albumin permeability of isolated rat glomeruli, and on tissue phosphorylation and urine albumin after acute or chronic CLCF-1 injection. In addition, cell sorting was performed to determine the presence of cells expressing CLCF-1 in spleen and bone marrow of normal mice and the effect of CLCF-1 infusion on splenic B-cell populations. CLCF-1 increased phosphorylation of STAT3 in multiple cell types, activated podocytes leading to formation of lamellipodia and decrease in basal stress fibers, increased glomerular albumin permeability, and increased STAT3 phosphorylation of peripheral blood cells and renal cortex. CLCF-1 increased urine albumin/creatinine ratio in mice and increased B-cell expression of IgG in mouse spleen. We conclude that CLCF-1 has potentially important systemic effects, alters podocyte function, and may contribute to renal dysfunction and albuminuria.


1990 ◽  
Vol 10 (8) ◽  
pp. 4334-4344
Author(s):  
D Read ◽  
T Nishigaki ◽  
J L Manley

To investigate the factors contributing to regulation of expression of the Drosophila segmentation gene even-skipped (eve), we have analyzed both the in vitro transcription and eve-promoter-binding proteins in embryo extracts. We show that the eve promoter is accurately and efficiently expressed in nuclear extracts derived from Drosophila embryos and that transcription is more efficient in extracts prepared from embryos at early stages of development than in those from older embryos, broadly reproducing the temporal pattern of expression observed in vivo. This stage-specific expression is dependent on sequences upstream of the eve transcription start site which contain multiple binding sites for at least two distinct proteins present in embryo nuclei. One of these proteins, the binding sites for which correspond to the sequences required for stage-specific expression, appears to be the previously described GAGA factor. Although the binding activity of the GAGA factor remains constant, the level of the binding activity of the other protein, which we have called the TCCT factor, changes during the course of embryogenesis. Activity is first detected 3 to 5 h after fertilization and decreases during later stages of embryogenesis. We discuss the possibility that the TCCT factor plays a role in the maintenance or refinement of the eve expression pattern.


Author(s):  
Julian E. Sale ◽  
Mats Bemark ◽  
Gareth T. Williams ◽  
Christopher J. Jolly ◽  
Michael R. Ehrenstein ◽  
...  

Following antigen encounter, two distinct processes modify immunoglobulin genes. The variable region is diversified by somatic hypermutation while the constant region may be changed by class–switch recombination. Although both genetic events can occur concurrently within germinal centre B cells, there are examples of each occurring independently of the other. Here we compare the contributions of class–switch recombination and somatic hypermutation to the diversification of the serum immunoglobulin repertoire and review evidence that suggests that, despite clear differences, the two processes may share some aspects of their mechanism in common.


2017 ◽  
Author(s):  
Neeraj Jain ◽  
Keenan Hartert ◽  
Saber Tadros ◽  
Warren Fiskus ◽  
Ondrej Havranek ◽  
...  

ABSTRACTThe activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) is characterized by the chronic activation of signaling initiated by immunoglobulin-μ (IgM). By analyzing DNA copy profiles of 1,000 DLBCLs, we identified gains of 18q21.2 as the most frequent genetic alteration in ABC-like DLBCL. We show that these alterations target the TCF4 (E2-2) transcription factor, and that over-expression of TCF4 leads to its occupancy on immunoglobulin gene enhancers and increased expression of IgM at the transcript and protein level. The TCF4 gene is one of the top BRD4-regulated genes in DLBCL. Using a BET proteolysis-targeting chimera (PROTAC) we show that TCF4 and IgM expression can be extinguished, and ABC-like DLBCL cells can be killed in vitro and in vivo. This highlights a novel genetic mechanism for promoting immunoglobulin signaling in ABC-like DLBCL and provides a functional rationale for the use of BET inhibitors in this disease.


2014 ◽  
Vol 112 (22) ◽  
pp. 6841-6847 ◽  
Author(s):  
Robert N. Plasschaert ◽  
Marisa S. Bartolomei

Growth-factor receptor bound protein 10 (Grb10) is a signal adapter protein encoded by an imprinted gene that has roles in growth control, cellular proliferation, and insulin signaling. Additionally, Grb10 is critical for the normal behavior of the adult mouse. These functions are paralleled by Grb10’s unique tissue-specific imprinted expression; the paternal copy of Grb10 is expressed in a subset of neurons whereas the maternal copy is expressed in most other adult tissues in the mouse. The mechanism that underlies this switch between maternal and paternal expression is still unclear, as is the role for paternally expressed Grb10 in neurons. Here, we review recent work and present complementary data that contribute to the understanding of Grb10 gene regulation and function, with specific emphasis on growth and neuronal development. Additionally, we show that in vitro differentiation of mouse embryonic stem cells into alpha motor neurons recapitulates the switch from maternal to paternal expression observed during neuronal development in vivo. We postulate that this switch in allele-specific expression is related to the functional role of Grb10 in motor neurons and other neuronal tissues.


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