WT1 Proteins
Genes, Wilms Tumor
Mice, Knockout
Wilms Tumor
Mice, Inbred C57BL
Mutation
Mice, Transgenic
Disease Models, Animal
Denys-Drash Syndrome
RNA, Messenger
Molecular Sequence Data
The Wilms' tumor suppressor gene (wt1) product regulates Dax-1 gene expression during gonadal differentiation. (1/612)
Gonadal differentiation is dependent upon a molecular cascade responsible for ovarian or testicular development from the bipotential gonadal ridge. Genetic analysis has implicated a number of gene products essential for this process, which include Sry, WT1, SF-1, and DAX-1. We have sought to better define the role of WT1 in this process by identifying downstream targets of WT1 during normal gonadal development. We have noticed that in the developing murine gonadal ridge, wt1 expression precedes expression of Dax-1, a nuclear receptor gene. We document here that the spatial distribution profiles of both proteins in the developing gonad overlap. We also demonstrate that WT1 can activate the Dax-1 promoter. Footprinting analysis, transient transfections, promoter mutagenesis, and mobility shift assays suggest that WT1 regulates Dax-1 via GC-rich binding sites found upstream of the Dax-1 TATA box. We show that two WT1-interacting proteins, the product of a Denys-Drash syndrome allele of wt1 and prostate apoptosis response-4 protein, inhibit WT1-mediated transactivation of Dax-1. In addition, we demonstrate that WT1 can activate the endogenous Dax-1 promoter. Our results indicate that the WT1-DAX-1 pathway is an early event in the process of mammalian sex determination. (+info)A zinc finger truncation of murine WT1 results in the characteristic urogenital abnormalities of Denys-Drash syndrome. (2/612)
The Wilms tumor-suppressor gene, WT1, plays a key role in urogenital development, and WT1 dysfunction is implicated in both neoplastic (Wilms tumor, mesothelioma, leukemias, and breast cancer) and nonneoplastic (glomerulosclerosis) disease. The analysis of diseases linked specifically with WT1 mutations, such as Denys-Drash syndrome (DDS), can provide valuable insight concerning the role of WT1 in development and disease. DDS is a rare childhood disease characterized by a nephropathy involving mesangial sclerosis, XY pseudohermaphroditism, and/or Wilms tumor (WT). DDS patients are constitutionally heterozygous for exonic point mutations in WT1, which include mutations predicted to truncate the protein within the C-terminal zinc finger (ZF) region. We report that heterozygosity for a targeted murine Wt1 allele, Wt1(tmT396), which truncates ZF3 at codon 396, induces mesangial sclerosis characteristic of DDS in adult heterozygous and chimeric mice. Male genital defects also were evident and there was a single case of Wilms tumor in which the transcript of the nontargeted allele showed an exon 9 skipping event, implying a causal link between Wt1 dysfunction and Wilms tumorigenesis in mice. However, the mutant WT1(tmT396) protein accounted for only 5% of WT1 in both heterozygous embryonic stem cells and the WT. This has implications regarding the mechanism by which the mutant allele exerts its effect. (+info)YAC complementation shows a requirement for Wt1 in the development of epicardium, adrenal gland and throughout nephrogenesis. (3/612)
The Wilms' Tumour gene WT1 has important functions during development. Knock-out mice were shown to have defects in the urogenital system and to die at embryonic day E13.5, probably due to heart failure. Using a lacZ reporter gene inserted into a YAC construct, we demonstrate that WT1 is expressed in the early proepicardium, the epicardium and the subepicardial mesenchymal cells (SEMC). Lack of WT1 leads to severe defects in the epicardial layer and a concomitant absence of SEMCs, which explains the pericardial bleeding and subsequent embryonic death observed in Wt1 null embryos. We further show that a human-derived WT1 YAC construct is able to completely rescue heart defects, but only partially rescues defects in the urogenital system. Analysis of the observed hypoplastic kidneys demonstrate a continuous requirement for WT1 during nephrogenesis, in particular, in the formation of mature glomeruli. Finally, we show that the development of adrenal glands is also severely affected in partially rescued embryos. These data demonstrate a variety of new functions for WT1 and suggest a general requirement for this protein in the formation of organs derived from the intermediate mesoderm. (+info)Tumor-associated WT1 missense mutants indicate that transcriptional activation by WT1 is critical for growth control. (4/612)
The WT1 gene encodes a zinc finger DNA binding transcription factor and is mutated in up to 15% of Wilms tumor cases. The WT1 protein binds to the promoters of many genes through GC- or TC-rich sequences and can function both as a transcriptional repressor and an activator in co-transfection assays depending on the cell type, the structure of the test promoter, and even the expression vectors used. Engineered expression of WT1 can lead to growth suppression by both cell cycle arrest and induction of apoptosis. However, the transcriptional activity of WT1 that is required for growth control was not defined. We found that three N-terminal tumor-associated missense mutations of WT1 were defective for activation of both a synthetic reporter containing WT1-binding sites as well as the promoter of a WT1 responsive gene, p21. These mutants failed to inhibit cell growth but still retain their ability to repress several putative WT1 target promoters. These results indicate that activation and not repression by WT1 is the critical transcriptional activity of the protein responsible for its growth suppressing properties. (+info)Analysis of native WT1 protein from frozen human kidney and Wilms' tumors. (5/612)
The Wilms' tumor susceptibility gene, WT1, is altered in a subset of Wilms' tumors and encodes a transcription factor with four zinc fingers. Here we describe the isolation of native WT1 protein from frozen normal human kidney and Wilms' tumor samples. Through size exclusion chromatography and Western blot analysis we determined the elution pattern of WT1. The majority of WT1 from adult kidney and Wilms' tumor specimens was found to elute at a size of approximately 120 kDa, consistent with a WT1 homodimer and some WT1 protein was also found in a higher molecular weight complex. In 14 week fetal kidney the majority of the WT1 protein eluted at a size of 80 kDa, suggesting that at this developmental stage the WT1 protein is not present as a homodimer. The identity of complexing partners can now be studied using this approach. (+info)The Wilms' tumor gene product represses the transcription of thrombospondin 1 in response to overexpression of c-Jun. (6/612)
Thrombospondin 1 (TSP1) is known for its significant anti-angiogenic properties. In a previous study, we have shown that transient or stable overexpression of the transcription factor c-Jun, in rat fibroblasts, leads to repression of TSP1. We now demonstrate that the c-Jun-induced repression of TSP1 does not occur directly and does not require binding of c-Jun to the TSP1 promoter. Instead, repression involves a factor secreted by c-Jun-overexpressing cells. This secreted factor triggers a signal transduction pathway from the membrane to the nucleus, and these signals lead to the binding of the product of the Wilms' tumor suppressor gene, WT1, to the -210 region of the TSP1 promoter. This region binds WT1 and SP1, but not EGR1, although its sequence fits the consensus binding site for this transcription factor. WT1 overexpression in transfected cells inhibits endogenous TSP1 gene expression and TSP1 transcription in experiments using TSP1 promoter-reporter constructs. The WT1 - KTS isoform is more active in repressing TSP1 transcription than WT1 + KTS, while EGR1 is inactive. Enhancement of WT1 binding to DNA in response to c-Jun does not require de novo protein synthesis. The above mechanism for TSP1 repression could apply to other genes, thus coordinating their regulation in the vicinity of a c-Jun-overexpressing cell. We conclude that WT1, which was discovered as a result of its tumor suppressor properties, may also possess oncogenic characteristics in the c-Jun transformation process, and thus repress the anti-angiogenic protein, TSP1. (+info)The Wilms' tumor suppressor gene (wt1) product represses different functional classes of transcriptional activation domains. (7/612)
We have studied the ability of the wt1 tumor suppressor gene product to repress different classes of activation domains previously shown to stimulate the initiation and elongation steps of RNA polymerase II transcription in vivo. Repression assays revealed that WT1 represses all three classes of activation domains: Sp1 and CTF, which stimulate initiation (type I), human immunodeficiency virus type I Tat fused to a DNA-binding domain, which stimulates predominantly elongation (type IIA), and VP16, p53 and E2F1, which stimulate both initiation and elongation (type IIB). WT1 is capable of exerting its repression effect over a significant distance when positioned approximately 1700 bp from the core promoter. Deletion analysis of WT1 indicates that the responsible domain resides within the first 180 N-terminal amino acids of the protein. Nuclear run-ons analyzing the effects of WT1 on initiation of transcription demonstrate inhibition of this process. Our observations imply that WT1 can repress activators that stimulate initiation and/or elongation. (+info)The Wilms' tumor suppressor, WT1, inhibits 12-O-tetradecanoylphorbol-13-acetate activation of the multidrug resistance-1 promoter. (8/612)
Overexpression of P-glycoprotein, the product of the multidrug resistance-1 (MDR1) gene, is associated with treatment failure in some hematopoietic tumors. Although expression of P-glycoprotein in normal hematopoietic cells is tightly regulated during hematopoietic differentiation, its aberrant overexpression in hematopoietic malignancies occurs at the transcriptional level. We have demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) increases transcription of the MDR1 gene and activates the MDR1 promoter, and that promoter activation by TPA requires binding of the zinc finger transcription factor EGR1 to specific MDR1 promoter sequences (C. McCoy and M. M. Cornwell, Mol. Cell. Biol., 15: 6100-6108, 1995). We demonstrate here that the Wilms' tumor (WT) suppressor, WT1, a member of the EGR family, inhibits the response of the MDR1 promoter to TPA in K562 cells. Inhibition is likely a direct effect of WT1 binding to the MDR1 promoter because: (a) WT1 expression does not inhibit the increase in EGR1 after TPA treatment; (b) inhibition by WT1 requires the zinc finger domain; (c) WT1 binds to MDR1 promoter sequences that bind EGR1 and are responsive to TPA; and (d) there is an inverse correlation between WT1 protein expression and MDR1 expression and promoter activity. These results suggest that the MDR1 gene is a target for regulation by WT1 and suggest mechanisms by which MDR1 may be regulated by WT1 and EGR1 during normal and aberrant hematopoiesis. (+info)Wilms' Tumor 1 (WT1) proteins are a group of transcription factors that play crucial roles in the development of the human body, particularly in the formation of the urinary and reproductive systems. The WT1 gene encodes these proteins, and mutations in this gene have been associated with several diseases, most notably Wilms' tumor, a type of kidney cancer in children.
WT1 proteins contain four domains: an N-terminal transcriptional activation domain, a zinc finger domain that binds to DNA, a nuclear localization signal, and a C-terminal transcriptional repression domain. These proteins regulate the expression of various target genes involved in cell growth, differentiation, and apoptosis (programmed cell death).
Abnormalities in WT1 protein function or expression have been linked to several developmental disorders, including Denys-Drash syndrome, Frasier syndrome, and Wilms' tumor. These conditions are characterized by genitourinary abnormalities, such as kidney dysplasia, ambiguous genitalia, and an increased risk of developing Wilms' tumor.
Wilms tumor (WT) genes, also known as WT1 and WT2, are tumor suppressor genes that play crucial roles in the normal development of the kidneys. Mutations or alterations in these genes can lead to the development of Wilms tumor, which is a type of kidney cancer that primarily affects children.
WT1 gene is located on chromosome 11p13 and encodes a transcription factor that regulates the expression of various genes involved in kidney development. Mutations in WT1 can lead to Wilms tumor, as well as other genetic disorders such as Denys-Drash syndrome and Frasier syndrome.
WT2 gene is located on chromosome 11p15 and encodes a zinc finger transcription factor that also plays a role in kidney development. Mutations in WT2 have been associated with an increased risk of Wilms tumor, as well as other genetic disorders such as Beckwith-Wiedemann syndrome.
It's worth noting that not all Wilms tumors are caused by mutations in WT1 or WT2 genes, and that other genetic and environmental factors may also contribute to the development of this type of cancer.
A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.
Wilms tumor, also known as nephroblastoma, is a type of kidney cancer that primarily affects children. It occurs in the cells of the developing kidneys and is named after Dr. Max Wilms, who first described this type of tumor in 1899. Wilms tumor typically develops before the age of 5, with most cases occurring in children under the age of 3.
The medical definition of Wilms tumor is:
A malignant, embryonal kidney tumor originating from the metanephric blastema, which is a mass of undifferentiated cells in the developing kidney. Wilms tumor is characterized by its rapid growth and potential for spread (metastasis) to other parts of the body, particularly the lungs and liver. The tumor usually presents as a large, firm, and irregular mass in the abdomen, and it may be associated with various symptoms such as abdominal pain, swelling, or blood in the urine.
Wilms tumor is typically treated with a combination of surgery, chemotherapy, and radiation therapy. The prognosis for children with Wilms tumor has improved significantly over the past few decades due to advances in treatment methods and early detection.
C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.
The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.
C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.
One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.
Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.
A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.
Transgenic mice are genetically modified rodents that have incorporated foreign DNA (exogenous DNA) into their own genome. This is typically done through the use of recombinant DNA technology, where a specific gene or genetic sequence of interest is isolated and then introduced into the mouse embryo. The resulting transgenic mice can then express the protein encoded by the foreign gene, allowing researchers to study its function in a living organism.
The process of creating transgenic mice usually involves microinjecting the exogenous DNA into the pronucleus of a fertilized egg, which is then implanted into a surrogate mother. The offspring that result from this procedure are screened for the presence of the foreign DNA, and those that carry the desired genetic modification are used to establish a transgenic mouse line.
Transgenic mice have been widely used in biomedical research to model human diseases, study gene function, and test new therapies. They provide a valuable tool for understanding complex biological processes and developing new treatments for a variety of medical conditions.
Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.
The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.
Examples of animal disease models include:
1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.
Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.
Denys-Drash Syndrome is a rare genetic disorder that affects the kidneys and genitalia. It is characterized by the development of Wilms' tumor, a type of kidney cancer, and abnormal genital development in males. The syndrome is caused by mutations in the WT1 gene, which plays a crucial role in the development of the kidneys and genitalia.
Individuals with Denys-Drash Syndrome typically have underdeveloped or absent male genitalia, and some may be born with ambiguous genitalia. They are also at an increased risk of developing Wilms' tumor, often during the first two years of life. In addition, many individuals with the syndrome develop kidney disease, which can progress to end-stage renal failure.
The management of Denys-Drash Syndrome typically involves close monitoring for the development of Wilms' tumor and kidney disease, as well as treatment with chemotherapy or radiation therapy if necessary. Kidney transplantation may also be required in cases of end-stage renal failure.
A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.
Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.
Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.
It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.