Simplified DNA Extraction Methods for Sexing Chick Embryos

A versatile bulk electrotransfection protocol for murine embryonic fibroblasts and iPS cells

Although electroporation has been widely accepted as the main gene transfer tool, there is still considerable scope to improve the electroporation efficiency of exogenous DNAs into primary cells. Here, we developed a square-wave pulsing protocol using OptiMEM-GlutaMAX for highly efficient transfection of murine embryonic fibroblasts (MEF) and induced pluripotency stem (iPS) cells using reporter genes as well as gRNA/Cas9-encoding plasmids. An electrotransfection efficiency of > 95% was achieved for both MEF and iPS cells using reporter-encoding plasmids. The protocol was efficient for plasmid sizes ranging from 6.2 to 13.5 kb. Inducing the error prone non-homologous end joining repair by gRNA/Cas9 plasmid transfection, a high rate of targeted gene knockouts of up to 98% was produced in transgenic cells carrying a single-copy of Venus reporter. Targeted deletions in the Venus transgene were efficiently (up to 67% deletion rate) performed by co-electroporation of two gRNA-encoding plasmids. We introduced a plasmid electrotransfection protocol which is straight-forward, cost-effective, and efficient for CRISPRing murine primary cells. This protocol is promising to make targeted genetic engineering using the CRISPR/Cas9 plasmid system.

Migration and differentiation of gonadal germ cells under cross-sex germline chimeras condition in domestic chickens

A series of experiments was conducted to investigate migration, proliferation and differentiation of gonadal germ cells (GGCs) collected from the gonads of 7-day-old chick embryos under cross-sex germline chimera conditions. The migratory and proliferative abilities of exogenous GGCs were examined by transferring 50 fluorescently labeled GGCs collected from White Leghorn (WL) embryos into the blood of 2-day-old Rhode Island Red (RIR) embryos. No significant difference was observed in the number of fluorescently labeled GGCs in the gonads of recipient embryos among any of the four possible donor and recipient sex combinations. Cross-sex germline chimeras were produced to examine the differentiation of GGCs by transferring 100 GGCs from WL embryos into 2-day-old RIR embryos. Exogenous-GGC-derived progeny were obtained from both male and female recipients, except when female GGCs were transferred into male recipients. The migratory ability of GGCs recovered from the 7-day-old embryonic gonad was not influenced by cross-sex germ cell transfer conditions, whereas the differentiation of the GGCs was affected by the sex combinations of GGCs donors and recipients.