BACKGROUND We previously established parthenogenetic mouse embryonic stem cells (ESCs) and this study was subsequently conducted for elucidating the influence of oocyte parthenogenesis on gene expression profile of ESCs. METHODS Gene expression of parthenogenetic ESC (pESC)-1 or pESC-2 was separately compared with that of two normally fertilized ESC (nfESC) lines (B6D2F1 and R1 strains), and quantification of mRNA expression was conducted for validating microarray data. RESULTS In two sets of comparison, reaction of 11 347 and 15 454 gene probes were altered by parthenogenesis, while strain difference changed the expression of 15 750 and 14 944 probes. Level of correlation coefficient was higher in the comparisons between normal fertilization and parthenogenesis (0.974-0.985) than in the comparisons between strains of nfESCs (0.97-0.971). Overall, the expression of 3276-3329 genes was changed after parthenogenesis, and 88% (96/109) of major functional genes differentially (P < 0.01) expressed in one comparison set showed the same change in the other. When we monitored imprinted genes, expression of nine paternal and eight maternal genes were altered after parthenogenesis and 88% (14/16) of these was confirmed by mRNA quantification. CONCLUSIONS The change in gene expression after parthenogenesis was similar to, or less than, the change induced by a strain difference under a certain genetic background. These results may suggest the clinical feasibility of parthenogenesis-derived, pluripotent cell
