Abstract: A receptor is provided having a heterologous binding site that activates, when bound, a signaling domain related to the TNF receptor superfamily. Methods/uses of the foregoing in whole cell biosensors are also provided. There is also provided a library comprising a plurality of unique biosensor cells for binding unknown binding substrates. Each unique biosensor is a host cell having a receptor which signals production of a positive selectable marker and/or a negative selectable marker in response to the receptor being bound. Also provided is a method of identifying biosensor cells from a library that is specifically activated by a target, involving (a) contacting the library with the target substrate under positive selection conditions; (b) contacting the library with a control substrate under negative selection conditions; and (c) identifying biosensor cells which survive (a) and (b) as biosensor cells which are specifically activated by the target.

Abstract: Methods of generating fusion protein variants are provided that comprise introducing sequence diversity at the junction region or regions in the fusion and allows for the generation of variants having a desired activity. Examples include immunoglobulins comprising a domain or polypeptide inserted into, or replacing, a CDR. Also provided are polynucleotides encoding a fusion protein and comprising two or more RSSs, and compositions and host cells comprising same, as well as fusion proteins variants produced by the described methods.

Abstract: Methods of generating fusion protein variants are provided that comprise introducing sequence diversity at the junction region or regions in the fusion and allows for the generation of variants having a desired activity. Examples include immunoglobulins comprising a domain or polypeptide inserted into, or replacing, a CDR. Also provided are polynucleotides encoding a fusion protein and comprising two or more RSSs, and compositions and host cells comprising same, as well as fusion proteins variants produced by the described methods.

Abstract: Compositions and methods are disclosed for generating immunoglobulin structural diversity in vitro, and in particular, for reducing biases in V region and J segment gene utilization, and for generating immunoglobulin V-D-J recombination events in a manner that does not require D-J recombination to precede V-DJ recombination. Selection of advantageous combinations of immunoglobulin gene elements, including introduction of artificial diversity (D) segment genes and optimization of recombination signal sequence (RSS) efficiency, are disclosed.

Abstract: Compositions and methods are disclosed for generating immunoglobulin structural diversity in vitro, and in particular, for reducing biases in V region and J segment gene utilization, and for generating immunoglobulin V-D-J recombination events in a manner that does not require D-J recombination to precede V-DJ recombination. Selection of advantageous combinations of immunoglobulin gene elements, including introduction of artificial diversity (D) segment genes and optimization of recombination signal sequence (RSS) efficiency, are disclosed.