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K-sam-related gene, N-sam, encodes fibroblast growth factor receptor and is expressed in T-lymphocytic tumors
Y Hattori1, H Odagiri, O Katoh
1Genetics Division, National Cancer Center Research Institute, Tokyo, Japan.
Abstract:
We recently reported the isolation of the K-sam complementary DNA (cDNA), which was amplified preferentially in poorly differentiated types of stomach cancer and codes for one of the heparin-binding growth factor or fibroblast growth factor (FGF) receptor families. The K-sam-related gene, N-sam (NCC-IT-cell-derived sam), was isolated by screening of the cDNA libraries of human immature teratoma cells, NCC-IT. Sequence analysis of the N-sam cDNAs showed that N-sam encodes a human FGF receptor, the FLG protein. N-sam was expressed in lymphocytic leukemia/lymphoma cells, predominantly in the thymic T-cell phenotype. In a T-cell leukemia line, MOLT3, N-sam mRNA expression was markedly enhanced by 12-O-tetradecanoylphorbol-13-acetate treatment and was also up-regulated by basic FGF exposure. These results indicate that N-sam expression is regulated during T-cell ontogeny and modulated by its putative ligand exposure. The results also suggested that interaction between immature T-cell and marrow or thymic interstitial cells might be mediated by N-sam and basic FGF stored in the extracellular matrix of stromal cells.
Insights
Researchers identified N-sam, a human fibroblast growth factor (FGF) receptor, in immature T-cells. N-sam expression is regulated during T-cell development and may mediate interactions between T-cells and stromal cells.
Area of Science:
- Molecular Biology
- Cell Biology
- Immunology
Background:
- K-sam cDNA is amplified in poorly differentiated stomach cancer and codes for a fibroblast growth factor (FGF) receptor.
- N-sam (NCC-IT-cell-derived sam) is a K-sam-related gene isolated from human immature teratoma cells (NCC-IT).
Purpose of the Study:
- To characterize the N-sam gene and its encoded protein.
- To investigate the expression and regulation of N-sam in hematopoietic cells, particularly T-cells.
- To explore the potential role of N-sam in T-cell development and cell-cell interactions.
Main Methods:
- cDNA library screening
- Sequence analysis of N-sam cDNAs
- Analysis of N-sam mRNA expression in T-cell lines (e.g., MOLT3) using techniques like Northern blotting or RT-PCR (implied).
- Treatment of T-cell lines with 12-O-tetradecanoylphorbol-13-acetate and basic FGF.
Main Results:
- N-sam encodes a human FGF receptor, identified as the FLG protein.
- N-sam is expressed in lymphocytic leukemia/lymphoma cells, with a predominant thymic T-cell phenotype.
- N-sam mRNA expression in the T-cell line MOLT3 is upregulated by 12-O-tetradecanoylphorbol-13-acetate and basic FGF.
- N-sam expression appears to be regulated during T-cell ontogeny and modulated by FGF ligand exposure.
Conclusions:
- N-sam is a human FGF receptor expressed in T-cells.
- N-sam expression is developmentally regulated and responsive to its ligand, basic FGF.
- N-sam and basic FGF may mediate interactions between immature T-cells and stromal cells in the bone marrow or thymus.