Development of an Economic Process to Store and Recover Homozygous Mouse Strains

描述(由申请人提供)：实验室小鼠是研究人类疾病的关键模型，主要是因为小鼠和人类的基因组惊人地相似。通过破坏基因或插入人类基因来修改小鼠基因组的能力，使研究人员能够开发出高度特异的菌株进行研究，并导致菌株的数量和复杂性呈指数级增长。创造这些菌株并非易事，必须通过培育近亲动物来保持复杂菌株的纯合性；否则，非连锁基因座将在后代中分离，菌株特征将被破坏。超低温保存用于存储未被积极研究的菌株，并在繁殖菌落丢失时保护菌株。然而，在冷冻保存或恢复期间，使用野生型卵子捐赠者，不能保持菌株的纯合性。此外，现有的超低温保存和储存菌株的方法昂贵、耗时，而且需要许多动物。迫切需要开发一种以保留原始基因的方式冷冻保存菌株的方法。这种方法必须是快速、经济的，并且使用的动物很少。将开发常规和新型辅助生殖技术的组合，以存档和恢复纯合菌株。与目前的胚胎冷冻保存方法相比，这些过程使用的资源将减少3-5倍。纯合子菌株将通过冷冻保存精子和卵巢来存档。然后，将使用外科人工授精(外科AI)和卵巢移植的组合来重组菌株。此外，还将探索系列卵巢移植和手术取卵方法，作为回收冷冻保存的精子和卵巢的替代方法。将开发冷冻室菌株的重组，以反映科学界的不同需求，并将提供：i)快速和低成本的回收，提供2-3个纯合子繁殖对；以及ii)中等快速的高成本回收，提供=10个纯合子繁殖对。 公共卫生相关性(由申请者提供)：辅助生殖技术现在占第一世界国家所有出生人口的5%以上。人类体外受精的一个主要限制是卵母细胞的稀少。我们的研究将有助于理解，并有望提高人类的卵母细胞生产率。

DESCRIPTION (provided by applicant): The laboratory mouse is a key model for the study of human diseases mainly because the mouse and human genomes are strikingly similar. The ability to modify the mouse genome by disrupting genes or inserting human genes allows researchers to develop highly specific strains for study and has led to an exponential growth in the number and complexity of strains. Creating these strains is not trivial and complex strains must be kept homozygous through breeding closely related animals; otherwise, non-linked loci will segregate among the offspring and strain characteristics will be disrupted. Cryopreservation is used to store strains that are not actively being studied and to protect strains if the breeding colony is lost. However, during cryopreservation or recovery wild type egg donors are used and the homozygosity of the strain is not maintained. In addition, the available methods to cryopreserve and store strains are expensive, time consuming, and require many animals. There is a pressing need to develop a method for cryopreserving strains in a manner which retains the original genotype. The method must be quick, economic, and use few animals. A combination of routine and novel assisted reproductive technologies will be developed to archive and recover homozygous strains. These processes will use 3-5 times fewer resources compared to current embryo cryopreservation methods. Homozygous strains will be archived by cryopreserving both sperm and ovaries. Strains will then be reconstituted using a combination of surgical artificial insemination (surgical AI) and ovarian transplant. Additionally, serial ovarian transplant and surgical oocyte retrieval methods will be explored as alternative methods to recover cryopreserved sperm and ovaries. The reconstitution of strains from the freezer will be developed to reflect the diverse needs of the scientific community and will provide: i) a fast and low cost recovery, delivering 2-3 homozygous breeding pairs, and ii) a moderately fast, higher cost recovery, delivering =10 homozygous breeding pairs. PUBLIC HEALTH RELEVANCE (provided by applicant): Assisted Reproductive Technologies now account for more than 5% of all births in the first world countries. A major limitation to human IVF is the paucity of oocytes. Our research will help understand and, hopefully, increase the oocytes productivity in humans.