Product details
Synonyms = Enhancer of split groucho 1 (ESG1); Transducin like enhancer of split 1; Transducin-like enhancer protein 1; Enhancer of split groucho-like protein 1; GRG1; TLE1
Antibody type = Recombinant Rabbit monoclonal / IgG
Clone = MSVA-856R
Positive control = Tonsil: A weak to moderate TLE1 staining should be seen in suprabasal cells of squamous epithelium and in a small subset of lymphocytes in germinal centres.
Negative control = Tonsil: The majority of lymphocytes in germinal centres should be TLE1 negative.
Cellular localization = Nucleus
Reactivity = Human
Application = Immunohistochemistry
Dilution = 1:100 – 1:200
Intended Use = Research Use Only
Relevance of Antibody
TLE1 is Overexpressed in 80% of synovial sarcomas.
Biology Behind
Transducin-like enhancer of split 1 (TLE1) is a member of the Groucho (Gro)/TLE family of transcriptional co-repressors. The TLE1 gene at chromosome 9q21.32 consists of 19 exons and encodes a 770 amino acid protein. TLE1 is a co-repressor of multiple other transcription factors. TLE1 does not bind to DNA but forms homo-oligomers and hetero-oligomers with other transcription factor proteins to inhibit their transcriptional activity. TLE1 interacts with several signal transduction pathways including the NF-kB Notch, Wnt/b-catenin, and Dpp/BMP/TGF-β signaling pathways. Accordingly, TLE1 regulates the transcriptional activity of a wide range of genes and has been implicated in embryogenesis, hematopoiesis, sex determination, neuronal and terminal epithelial differentiation, or cell proliferation and migration. TLE1 plays a role in the regulation of inflammation and in cancer progression.
Staining Pattern in Normal Tissues
Images describing the TLE1staining pattern in normal tissues obtained by the antibody MSVA-856R are shown in our “Normal Tissue Gallery”.
| Brain | Cerebrum | Weak to moderate TLE1 staining of subsets of glial and neuronal cells. |
| Cerebellum | Weak to moderate TLE1 staining of subsets of glial and neuronal cells. | |
| Endocrine Tissues | Thyroid | Weak TLE1 staining of follicular and endothelial cells. |
| Parathyroid | TLE1 staining is largely limited to endothelial cells. | |
| Adrenal gland | Weak TLE1 staining of a fraction of adrenocortical and medullary cells. | |
| Pituitary gland | Weak to moderate TLE1 staining of a fraction of epithelial cells of the adenohypophysis. | |
| Respiratory system | Respiratory epithelium | Weak to moderate TLE1 staining of a subset of (non-basal) epithelial cells. |
| Lung | Weak to moderate TLE1 staining of mostly vascular cells. | |
| Gastrointestinal Tract | Salivary glands | Moderate to strong TLE1 staining of serous glandular cells. Staining is weaker in mucinous cells and largely absent in excretory ducts. |
| Esophagus | Weak TLE1 staining of squamous epithelium, predominantly of the suprabasal cell layers. | |
| Stomach | Weak to moderate TLE1 staining in epithelial cells. Staining is always somewhat stronger in the surface epithelium than in glands. | |
| Colon | Weak to moderate TLE1 staining in epithelial cells. Staining is often stronger in crypts than at the surface. Potential exception: In the appendix, the TLE1 staining intensity may be highest at the surface and weaker in the crypts. | |
| Duodenum | Some TLE1 staining can occur in epithelial cells. Staining is stronger in crypts than in villi. Weak to moderate TLE1 staining of Brunner glands. | |
| Rectum | Weak to moderate TLE1 staining in epithelial cells. Staining is often stronger in crypts than at the surface. | |
| Small intestine | Some staining can occur in epithelial cells. Staining is stronger in crypts than in villi. | |
| Liver | Weak to moderate TLE1 staining of bile duct cells. Faint staining of hepatocytes. | |
| Gallbladder | Moderate TLE1 staining in epithelial cells. | |
| Pancreas | Weak to moderate TLE1 staining of acinar, islet, and ductal cells. | |
| Genitourinary | Kidney | Weak to moderate TLE1 staining of a subset of tubular cells. Staining is particularly strong in altered tubuli such as in case of atrophy. Staining appears to be less intense in collecting ducts. Weak to moderate staining of few glomerular cells and of cells of parietal layer of the Bowman capsule. |
| Urothelium | Weak to moderate TLE1 staining of urothelial cells (somewhat more in upper cell layers). | |
| Male genital | Prostate | Weak to moderate TLE1 staining in acinar cells. Staining is weak or absent in basal cells. |
| Seminal vesicles | TLE1 staining of variable intensity in a subset of epithelial cells. | |
| Testis | Moderate to strong TLE1 staining of spermatogonia. | |
| Epididymis | Moderate to strong TLE1 staining in non-basal epithelial cells. | |
| Female genital | Breast | Moderate TLE1 staining of luminal epithelial cells. Staining of basal/myoepithelial cells is much less intense or absent. |
| Uterus, myometrium | Weak to moderate TLE1 positivity of smooth muscle cells. | |
| Uterus, ectocervix | Weak to moderate TLE1 staining of squamous epithelium, predominantly of the suprabasal cell layers. | |
| Uterus endocervix | Weak to moderate TLE1 staining of epithelial, stromal, and endothelial cells. | |
| Uterus, endometrium | Moderate to strong TLE1 staining of epithelial and stromal cells. | |
| Fallopian Tube | Moderate TLE1 staining of stromal cells and of a fraction of epithelial cells. | |
| Ovary | Weak staining of corpus luteum and granulosa cells. Strong staining of theca interna cells. Moderate to strong staining of endothelial cells with staining intensity perhaps being dependent on localization. The stroma is largely TLE1 negative (except endothelium). | |
| Placenta early | Moderate to strong TLE1 staining of trophoblast and some stroma cells. | |
| Placenta mature | TLE1 staining is weak to moderate in some stroma cells and in trophoblast cells. Strong staining of decidua cells. | |
| Amnion | Strong TLE1 staining of amnion cells. | |
| Chorion | Moderate to strong TLE1 staining of chorion cells. | |
| Skin | Epidermis | Weak to moderate TLE1 staining of squamous epithelium, predominantly of the suprabasal cell layers. In addition: Scattered, mostly basally intraepithelial cells with strong TLE1 positivity. |
| Sebaceous glands | Moderate to strong TLE1 positivity of sebaceous cells. | |
| Muscle/connective tissue | Heart muscle | A faint TLE1 positivity may occur in some cells. |
| Skeletal muscle | Moderate to strong TLE1 positivity of skeletal muscle cells. | |
| Smooth muscle | Weak to moderate TLE1 positivity of smooth muscle cells. | |
| Vessel walls | Moderate TLE1 positivity of a subset of spindle cells in the media of the aorta. | |
| Fat | Moderate TLE1 positivity of fat cells. | |
| Stroma | TLE1 positivity of varying intensity can be seen in all types. | |
| Endothelium | Weak to moderate TLE1 positivity of endothelial cells. | |
| Bone marrow/lymphoid | Bone marrow | Weak to strong TLE1 positivity of a significant fraction of cells. |
| Lymph node | Weak to moderate TLE1 staining in a subset of lymphocytes, predominantly in germinal centres. | |
| Spleen | Moderate to strong TLE1 staining of sinus endothelial cells. Weak to moderate TLE1 staining in a subset of lymphocytes. | |
| Thymus | Weak to moderate TLE1 staining of a subset of cells of corpuscles of Hassall’s and of few other cells. | |
| Tonsil | Weak to moderate TLE1 staining in a subset of lymphocytes, predominantly in germinal centres. Moderate TLE1 staining of a major subset of crypt epithelial cells and of surface squamous epithelium (predominantly of the suprabasal cell layers). | |
| Remarks | Some lymphocytes/inflammatory cells and other stroma cells show nuclear TLE1 staining in all organs. |
RNA and protein expression data of prostein findings are also described in the Human Protein Atlas (Tissue expression TLE1).
Positive control = Tonsil: A weak to moderate TLE1 staining should be seen in suprabasal cells of squamous epithelium and in a small subset of lymphocytes in germinal centres.
Negative control = Tonsil: The majority of lymphocytes in germinal centres should be TLE1 negative.
Staining Pattern in Relevant Tumor Types
TLE1 is strongly expressed in 80% of synovial sarcomas but TLE1 expression – often at a lower level – also occurs in a very broad range of other tumors.
The TCGA findings on TLE1 RNA expression in different tumor categories have been summarized in the Human Protein Atlas.
Compatibility of Antibodies
No data available at the moment
Protocol Recommendations
IHC users have different preferences on how the stains should look like. Some prefer high staining intensity of the target stain and even accept some background. Others favor absolute specificity and lighter target stains. Factors that invariably lead to more intense staining include higher concentration of the antibody and visualization tools, longer incubation time, higher temperature during incubation, higher temperature and longer duration of the heat induced epitope retrieval (slide pretreatment). The impact of the pH during slide pretreatment has variable effects and depends on the antibody and the target protein.
All images and data shown here and in our image galleries are obtained by the manual protocol described below. Other protocols resulting in equivalent staining are described as well.
Manual protocol
Freshly cut sections should be used (less than 10 days between cutting and staining). Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH 7,8 Target Retrieval Solution buffer. Apply MSVA-856R at a dilution of 1:150 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent) according to the manufacturer’s directions.
Potential Research Applications
- The diagnostic utility of TLE1 immunohistochemistry for diagnosing synovial sarcoma needs to be better specified.
- The prognostic role of TLE1 expression in tumors needs to be clarified.
- The functional role of TLE1 in cancer and inflammation is still unclear.
- TLE1 is a potential therapeutic target.
Evidence for Antibody Specificity in IHC
There are two ways how the specificity of antibodies can be documented for immunohistochemistry on formalin fixed tissues. These are: 1. Comparison with a second independent method for target expression measurement across a large number of different tissue types (orthogonal strategy), and 2. Comparison with one or several independent antibodies for the same target and showing that all positive staining results are also seen with other antibodies for the same target (independent antibody strategy).
Orthogonal validation: For proteins such as TLE1 which are expressed in virtually all tissues but restricted to specific cell types and cell compartments, orthogonal validation is not suited.
Comparison of antibodies: True expression of TLE1 in all cell types found to be TLE1 positive by MSVA-856R is corroborated by identical stainings obtained by another commercially available independent antibody (termed “validation antibody”).
