小鼠ES细胞种系嵌合体的获得

种系嵌合体的获得是实现ＥＳ细胞介导的转基因途径的决定步骤，ＥＳ细胞种系分化能力的保持是决定种系嵌合的前提条件，而事体的主种系嵌合体的获得则是判定ＥＳ细胞系是否具有种系分化能力的唯一方法，为考察本室新近建立的３种小鼠ＥＳ细胞系ＭＥＳＰＵ２１．ＭＥＳＰＵ２２和ＭＥＳＰＵ２９的种系分化能力，选用近交系Ｃ５７ＢＬ／６Ｊ及远交系ＫＭＷ和ＩＣＲ为受体胚胎提供者，分别通过囊胚注射法和８细胞期桑椹胚注射法进行了嵌

Formation of Germline Chimeras from MurineEmbryonic Stem Cell Lines

eneration of germline chimeras is the curcial step in ES cell-mediatedtransgenesis. The prerequisitr for germline chimerism is the maintenance of germlinedifferentiating potency of ES cells, whereas Productior of germline chimeras is theonly method to prove whether such potency is maintained. In order to investigate thegermline differentiating potency of three newly established ES cell lines ( MESPU21,MESPU22 and MESPU29), ES cells were introduced into host emtryos from inbredC57BL/6J and outbred KMW or ICR through blastocyst injection or 8-cell stagemorula injection. Totally 81 chimeras were obtained, among 42 test-bred ores, 19were germline transmitters assessed by coat analysis, as is the first report of EScell-embryo germline chimeras in China. MESFU21 and MESPU22 formed germlinechimeras in high frequency and most of those chimeras Froduced ES cell-derivedprogeny in high Froporuor, which Prcved that bcth ES cell lines retaired goodgermline differentiating potency and could be used as valuable cellular vehicles tointreduce genetic modifications into mouse genome.