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Lecture 26
Transgenesis with high capacity
vectors
Transgenesis with High-Capacity Vectors
• transgenes are complementary DNAs (cDNAs), small genes (<20 kb)
or parts of genes
• cDNAs are poorly expressed in mammalian cells
• In transgenesis, important gene- specific regulatory sequences
retained as part of the insert
•
• complete genes and multigene complexes (<100 kb) large for
conventional vectors
• need for high-capacity vectors
• eg. bacterial, P1 bacteriophage- derived, mammalian,
and yeast artificial chromosomes [ BACs, PACs,MACs and
YACs, respectively])
• carry genomic DNA ranging in size from 100 to
>1,000kb
• used for transgenesis
YAC transgenesis
• transgenic mice produced by microinjection of the pronucleus of
the fertilized egg or transfection of ES cells with YACs
• carry either an array of related genes or a single large gene
• used to study developmental processes
• as models for human disorders
• and for the production of human therapeutic agents.
YAC transgenesis
• For example, transgenic mice with the human globin gene cluster,
• covers about 250kb and contains five different
functional globin genes,
• express genes in a tissue-specific and timedependent manner that corresponds to the site
specificity and temporal pattern in humans.
YAC transgenesis
• production of mice that synthesize only
human antibodies
• Human monoclonal antibodies
• Xenomouse
Schematic representation of the κ and H
human immunoglobulin genes.