Cloned Transgenic Calves Produced from Nonquiescent Fetal Fibroblasts

TLDR

An efficient system for genetic modification and large‑scale cloning of cattle is important for agriculture, biotechnology, and human medicine. Actively dividing fetal fibroblasts were genetically modified with a marker gene, a clonal line selected, and fused to enucleated mature oocytes. Out of 28 embryos transferred to 11 recipient cows, three healthy, identical, transgenic calves were generated, and nuclear transfer extended the life‑span of near senescent fibroblasts—as shown by population doublings in lines derived from a 40‑day‑old fetal clone—demonstrating that this system can enable complex genetic modifications in cattle.

Abstract

An efficient system for genetic modification and large-scale cloning of cattle is of importance for agriculture, biotechnology, and human medicine. Here, actively dividing fetal fibroblasts were genetically modified with a marker gene, a clonal line was selected, and the cells were fused to enucleated mature oocytes. Out of 28 embryos transferred to 11 recipient cows, three healthy, identical, transgenic calves were generated. Furthermore, the life-span of near senescent fibroblasts could be extended by nuclear transfer, as indicated by population doublings in fibroblast lines derived from a 40-day-old fetal clone. With the ability to extend the life-span of these primary cultured cells, this system would be useful for inducing complex genetic modifications in cattle.