| abstract |
The present invention provides methods and compositions, and systems using such methods and compositions, for determining cellular status, such as the state of a protein of interest. [Solution] When the fusion protein has the function of a native protein, the system biologically consists of a sequence encoding an enzyme donor (ED) sequence fused to the reading frame for the sequence encoding the surrogate of the mammalian protein of interest. Providing active fusion protein production. A vector comprising a transcriptional and translational region functional in a mammalian host cell, a sequence encoding ED linked to multiple cloning sites, an enzyme acceptor (EA) protein or an enzyme acceptor sequence encoding the protein, is provided, , Complemented by ED to form a functional enzyme, eg, β-galactosidase, which is transformed by the enzyme to form a detectable substrate. Mammalian cells can be used and modified to provide specific functions such as, for example, expression of EA, overexpression of the protein of interest. The system is used to monitor fusion proteins as a surrogate for natural proteins. |