AGRICULTURAL BIOLOGY, 2015, V. 50, ¹ 4, pp. 458-466 Poultry transgenesis doi: 10.15389/agrobiology.2015.4.458rus doi: 10.15389/agrobiology.2015.4.458eng THE STUDY OF FACTORS AFFECTED THE GENE TRANSFER EFFICIENCY IN CHICKEN EMBRYONIC CELLS BY APPLICATION OF LENTIVIRAL VECTORS N.A. VOLKOVA1, I.K. FOMIN1, E.K. TOMGOROVA1, A.N. VETOKH1, E.R. MENNIBAEVA1, G. BREM2, N.A. ZINOVIEVA1 Federal Agency of Scientific Organizations, pos. <...> A b s t r a c t Lentivirus-mediated gene transfer is being the one of the attractive method for genetic modification of chicken (S.C. Chapman et al., 2005; C.A. Smith et al., 2009; N.A. Volkova et al., 2013). <...> However, the efficiency of thansgenesis of the chicken embryonic cells has been shown to be relatively low. <...> Therefore, a large number (60,000 to 100,000) of embryonic cells at the start of incubation and the virus preparations with high titers (about 109 particles per milliliter) remain one of a crucial problem the researchers are facing with when try to achieve a satisfactory transgene introduction. <...> The aim of the present study was to determine the optimal conditions for production and application of the modified lentiviral vector system of second generation for the transgenesis of chicken embryos. <...> The vector system consisted of three different plasmids: psPAX2, containing gag-pol genes; pLPG, coding envelop glycoprotein G of vesicular stomatitis virus (VVC-G) and pWPXL, the selfinactivated lentiviral vector, carrying (enhanced green fluorescence protein) gene under control of promoter region of the human elongation factor 1 alpha-encoding gene. <...> To produce the recombinant virus particles and to determine the virus titers we used human cell line 293T. <...> The injections of the virus preparations into the chicken embryos were performed at the different stages: from 20 to 24 hours (group 1) and from 50 to 55 hours (group 2) of incubation. <...> To detect the transgenesis efficiency and the number of the integrated copies of the transgene the total DNA was extracted from embryos on the day 7 of incubation and analyzed for the presence of specific sequences by real-time PCR. <...> The maximal titers of the virus preparations were produced by the ratio of the psPAX2, pLPG and pWCAG plasmids equal 1:1:3 and were 2.4½107 CFU/ml before ultracentrifugation and 6.2½108 CFU/ml after concentration <...>