PARENT SESSION

(W300) INTEGRITY OF MOUSE PLACENTA IN PARTHENOGENESIS.

Kawahara, Manabu^{1, 2}, Kumagai, Takuya¹, Obata, Yayoi^{1, 2}, Kono, Tomohiro^{1, 2}, ¹ Tokyo University of Agriculture, Tokyo, Japan² Bio-oriented Technology Research Advancement Institution (BRAIN), Tokyo, Japan

ABSTRACT- By our original oocyte reconstruction system using nuclear transfer, we produced ng^WT/fg^WT parthenogenotes (PE) containing both genomes from non-growing (ng^WT) and fully grown (fg^WT) oocytes, which develop into 13.5-day-old fetuses. Moreover, the induction of the appropriate expression of the Igf2 and H19 genes in ng^WT/fg^WT PE caused the extended development to term, in which non-growing oocytes donors from mutant mice with a 13-kilobase deletion in the H19 gene (ng^H19d13) were used for oocyte reconstruction. Although ng^H19d13/fg^WT PE forms placenta, precise analysis in the placentation have been lacked. We, therefore, carried out global gene expression analysis by oligonucleotide microarray and histological analysis to understand how the placenta supported the fetal development. In ng^H19d13/fg^WT PE, placentation was significantly improved compared with that of ng^WT/fg^WT PE. At E12.5, the placental weights in ng^H19d13/fg^WT PE was heavier than that of ng^WT/fg^WT. Histological analysis also showed that the formation of the spongiotrophoblast and labyrinth layers, the surface areas of labyrinth and giant cell differentiation were apparently restored. At E15.5 or E18.5, development was insufficient showing poor proliferation of labyrinth tissue. This might be due to inappropriate gene expressions from paternally imprinted region on the chromosome 12, which play important roles in placentation during the late gestation. In conclusion, the present study indicates that the normalization of H19/Igf2 gene expression paternally imprinting results in improvement of placentation, in ng^H19d13/fg^WT PE, but meantime, suggests that further apporopriate gene expressions are necessary to cause normal placentation.

KEY WORDS: parthenogenesis, placenta, H19, Igf2