Lanosterol 14α-demethylase encoded by the Cyp51 gene controls one of the key steps in cholesterol biosynthesis thereby playing an important housekeeping role. Additionally, Cyp51 produces an intermediate in germ cells, meiosis-activating sterol (MAS) that has been implicated in the control of meiosis and germ cell maturation by in vitro experiments. However, the in vivo role of Cyp51 and MAS in the germ cell development as well as in other tissues and processes is unclear. To test if Cyp51 is essential for embryo development and how lack of function of this enzyme affects cholesterol de novo production, we first developed a full knockout model that exhibited several prenatal ABS-like features leading to lethality at E15.0. We ascribe lethality to heart failure due to hypoplasia, ventricle septum, epicardial and vasculogenesis defects suggesting that Cyp51 deficiency is involved in heart development and coronary vessel formation. As the most likely downstream molecular mechanisms alterations in sonic hedgehog and retinoic acid signaling pathways were identified. Cyp51 knockout mice provide evidence that Cyp51 is essential for embryogenesis and due to vast similarity with the ABS syndrome abnormalities, they present an animal model for studying this syndrome in humans. To examine the effect Cyp51 inactivation on spermatogenesis and test the hypothesis about essential role of Cyp51 and its intermediate MAS in germ cell development we generated male germ specific Cyp51 knockout mice. The inactivation of gene Cyp51 in germ cells was 89 % efficient . Phenotypic analyses revealed no significant changes in the morphology of the germ cells, testis weight, daily sperm production and reproduction capacity in the Cyp51 knockout testis comparing to wildtypes. The results obtained in our study does not support the tested hypothesis. We allow the possibility that the incomplete inactivation of Cyp51 gene resulted in the rescue of the phenotype. It is also plausible that only minute amount of MAS is sufficient to perform the biological function. MAS could therefore be transported from the intersticial compartment and contributed to the normal development of the germ cells.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 3027848Transgenic methods allow development of animals with genetic modifications. In this textbook, methods will be explained particularly for laboratory animals. Impact of this field can be seen with the Nobel prize to this field in 2007 in M. J. Evans, M. R. Cappechij in O. Smithies. This chapter is confined to description of basic transgenesis methods fot he use in research. Better understanding of the background can help reserachers in better planning and more efficient experiments as well as more ethical use of genetically modified animals in research
F.03 Increased qualifications of the research and development staff
COBISS.SI-ID: 3174792