小鼠ES细胞种系嵌合体的获得

Formation of Germline Chimeras from MurineEmbryonic Stem Cell Lines

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，而嵌合体的制作及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合体构建实验。共获得嵌合体８１只，经毛色分析确定在进行测交的４２只嵌合体中有１９只是种系传递者，为国内小鼠ＥＳ细胞种系嵌合体的首例报道。在所考察的３种ＥＳ细胞系中，ＭＥＳＰＵ２ｌ和ＭＥＳＰＵ２２均能以较高效率获得种系嵌合体，并且多数种系嵌合体（１４／１９）可高效传递ＥＳ细胞来源的毛色性状，确凿证明两细胞系均具有较强的种系分化能力，可作为优良的细胞载体介导小鼠基因组进行的基因改造。

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.