Abstract: The invention is directed to a cell comprising a nucleic acid encoding an Activation Induced Deaminase (AID) polypeptide, a fusion protein comprising an AID polypeptide, and methods of using a nucleic acid encoding an AID polypeptide.

Abstract: The invention is directed to a cell comprising a nucleic acid encoding an Activation Induced Deaminase (AID) polypeptide, a fusion protein comprising an AID polypeptide, and methods of using a nucleic acid encoding an AID polypeptide.

Abstract: Provided is a method of establishing an innate cellular immune defense mechanism against infectious (non-cellular) nucleic acid in a vertebrate or in vertebrate cells, comprising deaminating deoxycytidine (dC) to deoxyuridine (dU) in an infecting viral or retroviral nucleic acid in a dose-dependent manner by introducing a cellular nucleic acid deaminase. Also provided are such nucleic acid deaminases and the gene(s) encoding same, and uses therefore including thereapuetic formulations, methods of treatment, assays and methods of mutagenesis. Included are nucleic acid deaminases from the APOBEC family, in which CEM15 (also known as APOBEC3G) is one such nucleic acid deaminase.

Abstract: Chimaeric or wholly foreign immunoglobulin is obtained from cells or body fluid of a transgenic animal which has had inserted into its germline genetic material that encodes for at least part of an immunoglobulin, of foreign origin or that can rearrange to encode a repertoire of immunoglobulins, i.e. derived from a different animal source. For example, wholly human immunoglobulins may be produced from a transgenic mouse, possibly in response to an immunogen subsequently introduced to the mouse.

Abstract: A novel enhancer, known as the K3'-enhancer, has been identified in the mouse immunoglobulin K locus, downstream of C.sub.K. The K3'-enhancer is B cell specific, is some sevenfold stronger than the K-intron enhancer and the region of the enhancer shows striking sequence homologies to the lymphotopic papovavirus, IgH and K-intron enhancers. The novel enhancer allows high level expression both in transfected cell lines and in transgenic mice, and may thus be used to enhance expression of genes in host cells, in vivo and in vitro. The novel enhancer is also found to increase somatic mutation of antibody genes in transgenic mice. The novel enhancer can also be use in gene therapy. Functionally equivalent enhancers are to be expected to occur downstream of C.sub.K of the immunoglobulin K locus of other species.