Erse 59-CTCCAGCAGGACCATGTGATC-39. The probe was prepared by 32P-dCTP labeling with random primer extension kit (Promega) and hybridized with blotting membrane by incubating overnight at 65uC in hybridization oven (Hoefer Scientific Instrument). The concentration of probe used for hybridization was 25 ng/mL. Membranes were washed three times at 65uC in 0.56SSC buffer containing 1 SDS after hybridization and exposed against film in dark cassette at 280uC for 24 hours. Then the film was developed as general protocol.To verify the integrant numbers observed in one-cut 11967625 genomic DNA, the southern blot with double-digested genomic DNA was performed along with the TA 02 standard curve which was generated by serial dilution of double-digested transgenic plasmid in parallel. For short, the plasmid was serially diluted from 120 pg (5 copies) to 24 pg (one copy). Each concentration of standard plasmid was converted into copy numbers per volume using the following {9 equation: N = C|10 |6:02|1023 , where N stands for copy M|660 number (copies/mL), C for concentration (ng/mL) and M for base pairs of the plasmid. Further, the integrants identified by counting the bands in single-digested genomic DNA southern blot was matched to the copy numbers determined in double-cut genomic DNA southern blot by quantification with standard curve.Figure 3. Analysis of the expression of GFP in transgenic lambs. (A) Embryos injected with lentivirus were cultured and developed to blastula and visualized by white and UV light (left panels) under microscope with magnification of 2006. Visualization of GFP expression in transgenic lambs (#1,#3,#7) and non-transgenic lamb control (NTC) were pictured under white light and UV light (middle panels). Visualization of GFP expression of horn in 1.5 year old transgenic lamb #7 and non-transgenic lamb pictured under white light and UV light (right panels). Arrows indicated the green fluorescence in transgenic sheep; (B) Proteins extracted from tail tips of eight transgenic lambs were subjected to immunoblotting with GFP antibody as described in Materials and Methods. b-actin levels were determined with an anti-b-actin antibody and used as loading control. doi:10.1371/journal.pone.0054614.gGeneration of Transgenic Sheep by LentivirusFigure 4. Expression of GFP in tissues of transgenic lambs observed by fluorescence imaging and assayed by western blotting. (A) Fluorescence imaging of the whole inner Arg8-vasopressin web organs of transgenic sheep under white light. (B-D) Fluorescence imaging of liver, kidney and lung of transgenic or NTC sheep. The upper are organs of the transgenic sheep and the lower are organs of the NTC sheep. (E) Expression of GFP in tissues assayed by western bloting. Proteins extracted from tissues of tail tip, kidney, lung, spleen and liver of #4 and #12 lambs were subjected to immunoblotting with GFP antibody as described in Materials and Methods. b-actin levels were determined with an anti-b-actin antibody as loading control. doi:10.1371/journal.pone.0054614.gFluorescence ImagingPhotomicrographs of embryo were taken under fluorescent microscope (ECLipse TE2000-U, Nikon) using Nis-Elements software. For transgenic sheep, GFP images were performed with a Wd-9403e UV portable device (61 Biological Instrument, Peking) fitted with UV filter and captured using a 5D-Mark 2 digital camera (Canon, 50 mm lens).SDS-polyacrylamide gel electrophoresis. Separated proteins were transferred to nitrocellulose (NC) membrane (Bio-Rad) and immune-blott.Erse 59-CTCCAGCAGGACCATGTGATC-39. The probe was prepared by 32P-dCTP labeling with random primer extension kit (Promega) and hybridized with blotting membrane by incubating overnight at 65uC in hybridization oven (Hoefer Scientific Instrument). The concentration of probe used for hybridization was 25 ng/mL. Membranes were washed three times at 65uC in 0.56SSC buffer containing 1 SDS after hybridization and exposed against film in dark cassette at 280uC for 24 hours. Then the film was developed as general protocol.To verify the integrant numbers observed in one-cut 11967625 genomic DNA, the southern blot with double-digested genomic DNA was performed along with the standard curve which was generated by serial dilution of double-digested transgenic plasmid in parallel. For short, the plasmid was serially diluted from 120 pg (5 copies) to 24 pg (one copy). Each concentration of standard plasmid was converted into copy numbers per volume using the following {9 equation: N = C|10 |6:02|1023 , where N stands for copy M|660 number (copies/mL), C for concentration (ng/mL) and M for base pairs of the plasmid. Further, the integrants identified by counting the bands in single-digested genomic DNA southern blot was matched to the copy numbers determined in double-cut genomic DNA southern blot by quantification with standard curve.Figure 3. Analysis of the expression of GFP in transgenic lambs. (A) Embryos injected with lentivirus were cultured and developed to blastula and visualized by white and UV light (left panels) under microscope with magnification of 2006. Visualization of GFP expression in transgenic lambs (#1,#3,#7) and non-transgenic lamb control (NTC) were pictured under white light and UV light (middle panels). Visualization of GFP expression of horn in 1.5 year old transgenic lamb #7 and non-transgenic lamb pictured under white light and UV light (right panels). Arrows indicated the green fluorescence in transgenic sheep; (B) Proteins extracted from tail tips of eight transgenic lambs were subjected to immunoblotting with GFP antibody as described in Materials and Methods. b-actin levels were determined with an anti-b-actin antibody and used as loading control. doi:10.1371/journal.pone.0054614.gGeneration of Transgenic Sheep by LentivirusFigure 4. Expression of GFP in tissues of transgenic lambs observed by fluorescence imaging and assayed by western blotting. (A) Fluorescence imaging of the whole inner organs of transgenic sheep under white light. (B-D) Fluorescence imaging of liver, kidney and lung of transgenic or NTC sheep. The upper are organs of the transgenic sheep and the lower are organs of the NTC sheep. (E) Expression of GFP in tissues assayed by western bloting. Proteins extracted from tissues of tail tip, kidney, lung, spleen and liver of #4 and #12 lambs were subjected to immunoblotting with GFP antibody as described in Materials and Methods. b-actin levels were determined with an anti-b-actin antibody as loading control. doi:10.1371/journal.pone.0054614.gFluorescence ImagingPhotomicrographs of embryo were taken under fluorescent microscope (ECLipse TE2000-U, Nikon) using Nis-Elements software. For transgenic sheep, GFP images were performed with a Wd-9403e UV portable device (61 Biological Instrument, Peking) fitted with UV filter and captured using a 5D-Mark 2 digital camera (Canon, 50 mm lens).SDS-polyacrylamide gel electrophoresis. Separated proteins were transferred to nitrocellulose (NC) membrane (Bio-Rad) and immune-blott.