Transgenic chickens with an inactivated endogenous gene locus

Abstract

The present invention is transgenic chickens obtained from long-term cultures of avian PGCs and techniques to produce and transgenic birds derived from prolonged PGC cultures. In some embodiments, these PGCs can be transfected with genetic constructs to modify the DNA of the PGC, specifically to introduce a transgene encoding an exogenous protein. When combined with a host avian embryo by known procedures, those modified PGCs are transmitted through the germline to yield transgenic offspring. This invention includes compositions comprising long-term cultures of PGCs and offspring derived from them that are genetically modified. The genetic modifications introduced into PGCs to achieve the gene inactivation may also include, but are not restricted to, random integrations of transgenes into the genome, transgenes inserted into the promoter region of genes, transgenes inserted into repetitive elements in the genome, site specific changes to the genome that are introduced using integrase, site specific changes to the genome introduced by homologous recombination, and conditional mutations introduced into the genome by excising DNA that is flanked by lox sites or other sequences that are substrates for site specific recombination.

Description

Background technique [0001] Transgenic animals offer the possibility of huge advances in the sustainable production of valuable pharmaceutical products such as antibodies. However, there are significant technical hurdles to the generation of transgenic animals, which have only been overcome in a few species. Incorporating a genetic modification encoding a foreign protein into the DNA of another species requires several different techniques, which must be developed for each species. One way to alter the genetic and physical characteristics of an animal is to introduce cells into the animal's recipient embryo. These cells can contribute to the tissue of the animal from the recipient embryo and can contribute to the genome of the resulting transgenic offspring of the animal. [0002] In some cases, the cells can be engineered with a transgene comprising DNA encoding an exogenous product such as a protein or antibody. The transgene contains the DNA that is blueprinted for the p...

AI Technical Summary

Problems solved by technology

[0012] Both random and targeted insertion of transgenes fail to excise the positive selection cassette from the transgene in transgenic animals

The presence of the selection cassette can lead to many problems, such as disrupted expression of genes adjacent to the locus due to strong transcriptional regulatory elements usually present in the selection cassette (Lerner et al. 1993 CD3zeta / eta / theta locus is colinear with and transcribed antisense to the geneencoding the transcription factor Oct-1. J Immunol.151: 3152-62; Ohno et al. 1994 Targeted disruption of the CD3 eta locus causes high lethality in mice: modulation of Oct-1 transcription on the opposite strand. EMBO J.13: 1157-65)

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