High impact information on Tcn2

• To delineate the location of receptors on these cells, we have constructed a visual probe by covalently coupling purified TCII-Cbl to submicrometre latex particles (minibeads) [1].
• We report here that when L1210 cells are incubated with minibeads containing TCII-Cbl at 4 degrees C and examined by scanning electron microscopy (SEM), the particles are found attached predominantly to microvilli [1].
• These observations suggest that adherence results from the ability of transcobalamin-II to form a bridge between immobilized cobalamin on the bead and receptors in the plasma membrane of the cell [2].
• Production of TCII (vitamin B12 transport protein) by mouse mononuclear phagocytes [3].
• With 5-methyltetrahydrofolate, optimal stimulation of growth was observed with free and transcobalamin-II-bound cobalamin at 4,000 pM and 2 pM, respectively [4].

Biological context of Tcn2

• These studies also establish a synteny group, including Lif and Tcn-2, the structural gene for transcobalamin 2, that is conserved between man and mouse [5].
• Analysis of mouse specific chromosomal enzyme markers in relationship to TCN-2 secretion, in the hybrid clones, provided provisional evidence for assignment of the Tcn-2 locus to chromosome 11 [6].
• Somatic cell hybrids, recombinant inbred (RI) mouse strains, and backcross breeding experiments were used to locate the gene of transcobalamin II (Tcn-2), the vitamin B12 binding protein in mouse serum [6].
• Localization of the gene for the vitamin B12 binding protein, transcobalamin II, near the centromere on mouse chromosome 11, linked with the hemoglobin alpha-chain locus [6].
• Rapidly dividing cells up-regulate the number of transcobalamin II receptors during DNA replication [7].

Anatomical context of Tcn2

• The data from this study demonstrate a negative correlation between growth activity and TC-II secretion in the J774 cell line [8].
• It has been concluded that the PEC macrophages synthesize TCII [9].
• Mouse monocytes and fibroblasts secreted considerably larger quantities of TCII than did their human counterparts [10].
• Murine thymus cells of T lymphocyte tumors secreted only small quantities of TCII [10].
• The synthesis of transcobalamin II, a vitamin B12 transport protein, by stimulated mouse peritoneal macrophages [9].

Associations of Tcn2 with chemical compounds

• The modulation of transcobalamin II (TC-II) production by cyclic adenosine 3',5'-monophosphate in the murine macrophage cell line J774: relationship to growth behavior [8].
• We undertook a study to define the role of cyclic AMP [cAMP] in modulating the secretion of transcobalamin II (TC-II) in the mouse macrophage like cell line J774 [8].

Other interactions of Tcn2

• The linkage group Tcn-2/wa-2/Hba was established [6].

Analytical, diagnostic and therapeutic context of Tcn2

• Lectin-agarose immobilization, a new method for detecting soluble membrane receptors. Application to studies with epidermal growth factor-urogastrone and transcobalamin-II [11].
• In addition, isolation of the TC II in some animal sera by gel filtration may result in a TC II that is more hydrophobic than the native molecule [12].
• This bioassay has allowed us to demonstrate that several monoclonal antibodies, raised against TCII, are potent inhibitors of cell proliferation and that excess Cbl abrogates this inhibitory effect [13].
• We have established cell culture conditions which allow reproducible measurements of cell proliferation that is dependent on Cbl and its carrier protein, TCII [13].

References