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The electronic form of this document may be cited in the following style:
Human Genome Program, U.S. Department of Energy, DOE Human Genome Program Contractor-Grantee Workshop IV, 1994.

Abstracts scanned from text submitted for November 1994 DOE Human Genome Program Contractor-Grantee Workshop. Inaccuracies have not been corrected.

Construction of a 2 Mb YAC library in transgenic mice of human chromosome 21q22.2

Desmond J.Smith, Yiwen Zhu, Jan-Fang Cheng, Edward M. Rubin
Human Genome Center, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720

Libraries of the human genome have been made in bacteria, yeast and somatic cells. These libraries have been of use for the identification of genes based upon screens for sequence, expression and complementation of function in vitro. We are presently expanding this strategy by creating in vivo libraries of transpolygenic mice (mice with large transgene inserts likely to contain several genes). Genes within the introduced human DNA may be screened for through the assessment of altered phenotype in members of the library. We have constructed an initial library which focuses on the Down syndrome region of chromosome 21, a region syntenic to the segment of murine chromosome 16 where the mutation, Weaver, has been mapped. This murine mutation is characterized by cerebellar ataxia and hypotonia.

Using microinjection into fertilized mouse eggs, transpolygenic mice have been created containing each of one of the following overlapping YACs from 21q22.2: 230E8 (700kb), 141G6 (500kb), 152F7 (550kb) and 285E6 (400kb). The YAC DNA, now as part of the mouse genome, was mapped and in approximately 35% of the transpolygenic lines the full length YAC was present. Between two to five independent lines of mice containing an intact YAC was created for each of the 4 YACs from this region. The remainder possessed partial fragments of these YACs and these lines will be a useful as a fine structure genetic mapping resource. There is a gap in the contig between YACs 230E8 and 141G6. We have utilized the availability of overlapping P1s for this area to create multiple lines of transpolygenic mice containing 6 P1s which cover the gap. This was achieved by pooling the DNA of the P1 phage together before microinjection.

Together, the transpolygenic animals harbor about 2 Mb of human DNA from the Down syndrome region. Individual members of this in vivo library are being assessed for the phenotypic features associated with trisomy 21q22 (heart disease, hematopoietic abnormalities, dysmorphic facies, developmental delays etc.). In addition, since the DNA in the transpolygenic mice encompasses the entire genetic interval to which the Weaver gene has been mapped we are in the processes of mapping / cloning this gene by mating members of the in vivo library with Weaver homozygous animals and assessing the offspring for in vivo complementation of the Weaver phenotype.