Bowen R A, Reed M L, Schnieke A, Seidel G E, Stacey A, Thomas W K, Kajikawa O
Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins 80523.
Biol Reprod. 1994 Mar;50(3):664-8. doi: 10.1095/biolreprod50.3.664.
Producing transgenic cattle by microinjection of DNA into pronuclei has been inefficient and costly, in large part because of the cost of maintaining numerous nontransgenic pregnancies to term. We designed a system for early identification of transgenic embryos in which biopsies of embryos were assayed by polymerase chain reaction for presence of the transgene before embryo transfer. A total of 2555 embryos were microinjected with one of two DNA constructs. Of the 533 embryos biopsied, 112 were judged to be potentially transgenic and were transferred nonsurgically to recipients, resulting in production of 29 putative transgenic fetuses. One fetus and one calf (7% of offspring) were subsequently shown to be definitively transgenic. The calf was transgenic for a chicken c-ski cDNA, and several months after birth developed dramatic muscular hypertrophy followed by muscle degeneration. This phenotype was associated with expression of high levels of mRNA from the transgene.
通过将DNA显微注射到原核中来生产转基因牛效率低下且成本高昂，在很大程度上是因为维持大量非转基因妊娠至足月的成本。我们设计了一种用于早期鉴定转基因胚胎的系统，在该系统中，在胚胎移植前通过聚合酶链反应检测胚胎活检组织中是否存在转基因。总共2555个胚胎被显微注射了两种DNA构建体中的一种。在接受活检的533个胚胎中，112个被判定为可能是转基因胚胎，并通过非手术方式移植给受体，最终产生了29个推定的转基因胎儿。随后证实有1个胎儿和1头小牛（占后代的7%）确实是转基因的。这头小牛携带鸡c-ski cDNA转基因，出生几个月后出现了明显的肌肉肥大，随后肌肉发生退化。这种表型与转基因高水平mRNA的表达有关。
