Mice On The 17th Chromosome Total Length Of Mitotic Recombination System To Build And Balance Of Chromosomes Of,

The completion of mouse and human genome sequencing has paved the way of functional analysis of mammalian genes genome wide. However, elegant genetic tools such as mitotic recombination mediated mosaic analysis and balancer chromosomes are still limited in mouse. Mitotic recombination mediated mosaic analysis permits a variety of cellular and molecular studies, including lineage analysis and loss-of-function analysis in intact organisms, while balancer chromosomes are genetic reagents that play important roles in mutagenesis screen and stock maintenance. My thesis focused on establishing a mitotic recombination system and exploring new strategies towards a full-length balancer chromosome for mouse chromosome 17.To generate a mitotic recombination system, I have integrated recombination sites FRT and loxP, and exogenous markers such as hCD2, at the proximal end of chr. 17. Mitotic recombination events were stably observed in lymphocytes with the presence of T cell specific Lck-Cre. Ubiquitously expressed Pgk-Cre or Actin-Flp recombinase could also induce mitotic recombination, though the latter gave a lower efficiency. Thus, this recombination system could be utilized for mosaic analysis and mutational screens of the genes on chr. 17.Balancer chromosomes carry inversions that effectively suppress recombination between homologous chromosomes. To generate a balancer chromosome covering full-length mouse chr. 17, I have integrated loxP sequences along with marker genes into four selected loci so that three continuous inversions may be induced thereafter with minimal interference of the viability and fertility. As expected, single locus insertion did not cause developmental abnormalities in vivo. Mouse lines carrying two insertions were also generated from ES cell clones experienced three rounds of electroporation, indicating the feasibility of repeated chromosomal manipulations in ES cells. These studies provided a key step toward the development of a full-length mouse balancer chr. 17 with multiple inversions.