Transcript Chapter 8: Animal Models: Genetic Manipulation

Chapter 8: Animal Models:
Genetic Manipulation
Karen Lyons
From the Primer on the Metabolic Bone Diseases
and Disorders of Mineral Metabolism, 7th Edition.
www.asbmrprimer.org
Figure 1
Figure 1 Steps involved in generation of a knockout mouse model. (A) A targeting construct consisting of a
neomycin-positive selection cassette (neo) inserted into or in place of an exon essential for the normal
function of the target gene is generated. (B) The construct is introduced into ES cells (derived from 129
strain mice, agouti coat color) by electroporation. (C) Drug selection is used to select for colonies in which
the construct has integrated stably. (D) Homologous recombinants are distinguished from colonies in which
the targeted construct has integrated randomly by Southern blot analysis. (E) Correctly targeted ES cells
are microinjected into a blastocyst derived from a host of a different genetic background (e.g., C57BL/6,
black coat color) and transplanted into a pseudopregnant female. (F) Injected blastocysts are transplanted
into a host pseudopregant female. (G) Resulting chimeric offspring (mixed coat color) are backcrossed to a
mouse of the same genetic background as the host blastocyst (e.g., C57BL/6) to obtain agouti offspring
that are derived from the 129 strain ES cells and therefore are heterozygous for the targeted allele.
© 2008 American Society for Bone and Mineral Research