Purification and characterisation of natural interferon ωl: two alternative cleavage sites for the signal peptidase. Adolf G.R., Maurer-Fogy I., Kalsner I., Cantell K.Monoclonal antibodies and enzyme immunoassays specific for human interferon (IFN) ωl: evidence that IFN-ωl is a component of human leukocyte IFN. Antigenic structure of human interferon col (interferon alpha II): comparison with other human interferons. Inhibition of the cellular response to interferons by products of the adenovirus type 5 E1A oncogene. Ackrill A.M., Foster G.R., Laxton C.D., Flavell D.M., Stark G.R., Kerr I.M.Accumulation and breakdown of RNA-deficient intracellular virus particles in interferon-treated NIH 3T3 cells chronically producing Moloney murine leukaemia v. IFNs can also stimulate indirect antiviral and antitumor mechanisms, depending upon cellular differentiation and the induction of cytotoxic activity. The biological activities of IFNs are mostly dependent upon protein synthesis with selective subsets of proteins mediating individual activities. IFN-α, as a mixture of subtypes, and IFN-ω may be produced together following viral infection of null lymphocytes or monocytes/macrophages. At the C-terminus, the aa sequence of IFN-ω is six residues longer than that of IFN-α or IFN-β proteins. IFN-ω contains 195 aa-the N-terminal 23 comprising the signal sequence and the remaining 172, the mature IFN-ω protein. Pre-IFN-β contains 187 aa, of which 21 comprise the N-terminal signal polypeptide and 166 comprise the mature IFN-β protein. IFN-α subtypes are secreted proteins and as such are transcribed from mRNAs as precursor proteins, pre-IFN-α, containing N-terminal signal polypeptides of 23 hydrophobic amino acids (aa) mainly. They are synthesized from their respective mRNAs for relatively short periods following gene activation and are secreted to act, via specific cell surface receptors, on other cells. They are transiently expressed following induction by various exogenous stimuli, including viruses. The genes of three IFN subtypes are tandemly arranged on the short arm of chromosome 9. IFN omega (IFN-ω) is antigenically distinct from IFN-α and IFN-β but is molecularly related to both. Interferon β (IFN-β) is a single protein species and is molecularly related to IFN-α subtypes, although it is antigenically distinct from them. Interferon alpha (IFN-α) is a mixture of closely related proteins, termed “subtypes,” expressed from distinct chromosomal genes.
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