34 COMPARISON OF IN VIVO DEVELOPMENT DURING EARLY PREGNANCY OF CLONED FETUSES DERIVED FROM BOVINE FETAL FIBROBLASTS AT THE EARLY G1 AND G0 PHASES

Enhanced development of bovine somatic cell nuclear transfer (NT) embryos to full term has been achieved using fibroblasts at the early G1 (eG1) phase instead of cells at the quiescent (G0) phase (Urakawa et al. 2004 Theriogenology 62, 714–728). The high abortion rate and abnormal placental development of NT embryos using G0 phase cells is related to the low formation rate of embryonic disks and the aberrant development of the trophectoderm in utero until Day 14 of gestation (Ideta et al. 2007 Cloning Stem Cells 9, 571–580). The purpose of this study was to examine the morphological development of conceptuses such as fetuses and fetal membranes in the early pregnancy of NT embryos using eG1 phase cells (eG1-NT embryos) and G0 phase cells (G0-NT embryos). Blastocysts derived from eG1-NT and G0-NT embryos were transferred to recipient heifers, and the conceptuses at Day 50 of gestation were retrieved nonsurgically using prostaglandin F2α (PGF2α) and oxytocin (Lavoir and Betteridge 1996 J. Reprod. Fertil. 106, 95–100). In vitro-fertilized (IVF), parthenogenetic and artificially inseminated (AI) embryos were used as controls. Data were analyzed using chi-square test and Student’s t-test. Pregnancy rates at Day 30 of recipient heifers carrying eG1-NT, G0-NT, IVF, parthenogenetic, and AI embryos were similar (57 to 100%; 4/7 to 8/8). Two recipient heifers carrying parthenogenetic embryos returned to estrus between Day 30 and 50 of gestation, whereas all other pregnancies remained viable. Most fetuses at Day 50 of gestation of all experiment groups (20/24) were recovered nonsurgically by several PGF2α and oxytocin treatments. The recovery rates of normal fetuses derived from eG1-NT embryos (83%, 5/6), IVF embryos (80%, 4/5), and AI embryos (88%, 7/8) were greater than those of G0-NT embryos (33%, 2/6) and parthenogenetic embryos (0%, 0/7). The amniotic fluid volume of G0-NT embryos was significantly greater than that of AI embryos (P < 0.05). But the amniotic fluid volume of eG1-NT embryos was the same as that of AI embryos (P > 0.05). The fetal weights of eG1-NT and IVF embryos were significantly greater than the fetal weight of AI embryos (P < 0.05). Our results suggest that efficient production of cloned offspring is possible by NT using donor cells that are in the early G1 phase.

179 MODULATION OF RHOPHILIN-2 MAY REGULATE THE PROGRESSION OF CELL DIVISION IN FERTILIZED MOUSE EGGS

It has been reported that activity of Rho, one of the GTPases, is essential for division of nuclei and cytoplasm of fertilized mouse eggs. Since it has been reported that alteration of activities of GTPases modifies their ability to attach to each of their effector proteins in somatic cells, effector proteins seem to be able to control not only progression but also repression of cell division by changing their cellular localizations through activities of GTPases. For this reason, Rhophilin-2, one of the effector proteins of Rho, seems to be involved in the decision of progression of division of fertilized mouse eggs. To examine whether this involvement works in fertilized mouse eggs, cellular localization of Rho and Rhophilin-2 in fertilized mouse eggs that were treated with Rho inhibitor were analyzed. Moreover, cellular localization of GABA A receptor association protein (GABARAP), which was identified in our previous study (Matsuoka et al. 2006 Reprod. Fertil. Dev. 18, 176–177) as a protein that interacts with Rhophilin-2, was also analyzed. Fertilized mouse eggs were obtained from in vitro fertilization technique. One group of fertilized eggs was obtained at 24 h after insemination as experimental control. To obtain the mouse eggs in which Rho activities were inhibited, Clostridium botulinum C3 exoenzyme (C3-CB), an inhibitor of Rho activity, was injected into the other group of fertilized mouse eggs at 12 h after insemination, and were collected after 12 h of subsequent culture. Cellular localization of Rho (n = 100), Rhophilin-2 (n = 10). and GABARAP (n = 10) in the collected oocytes was analyzed by using immunofluorescence. Our results showed that Rho and Rhophilin-2 were co-localized at the midbody microtubule, which is an important device for cytoplasmic division in control eggs. However, the inhibition of Rho activity did not modify the co-localization of Rho and Rhophilin-2. On the other hand, localization of GABARAP was modified by the inhibition of Rho activity, and GABARAP was detected around the nuclei of fertilized eggs in which Rho activity was inhibited. In the next experiment, we examined whether interaction of Rhophilin-2 and GABARAP was modified by the inhibition of Rho activity by using a co-immunoprecipitation assay (co-IP) (n = 100). The interaction of Rhophilin-2 and GABARAP was found to disappear after inhibition of Rho activity. These results suggest that activity of Rho seems to regulate cytoplasmic division through Rhophilin-2 modification. Moreover, Rho seem to modulate the nuclear division of fertilized mouse eggs by regulating the interaction between Rhophilin-2 and GABARAP. This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan Mext and by a grant for the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technology Excellence of the JST.

40 EARLY DEVELOPMENT OF RECONSTRUCTED MOUSE EMBRYOS USING BONE MARROW CELLS FROZEN WITHOUT CRYOPROTECTANT

Animal cells frozen with suitable cryoprotectants have been successfully cryopreserved for long periods of time, maintaining viability upon thawing. Animal cells frozen without cryoprotectant, however, may suffer serious damage and not be useful as donors in somatic cell nuclear transfer (SCNT). However, in some cases, old animal samples were frozen only as a whole body or a piece of tissue without cryoprotectant. If the cells from such old samples could be useful for SCNT, then there are potentially many candidates where individual animals could be reproduced. In this study, we examined the possibility of using mouse bone marrow cells frozen without cryoprotectant as nuclear donors in SCNT. Thigh bones were collected from B6C3F1 mice and frozen in either a –25�C or a –80�C freezer for more than one month. Thawing of frozen bones was performed by placing them in an incubator at 37�C. Bone marrow cells were collected by washing the bone cavity with saline. Recipient oocytes for SCNT were collected from B6D2F1 female mice. The enucleation of recipient oocytes and the injection of nuclei were performed as previously reported (Wakayama et al. 1998 Nature 394, 369–374) with a piezo-actuated micromanipulator system. In this study, 4 groups of mouse cells (fresh bone marrow cells, bone marrow cells frozen at –25�C, bone marrow cells frozen at –80�C, and fresh cumulus cells) were used as the nuclear donors in SCNT. After nuclear injection, embryos were kept in mCZB medium for 1 h at 37�C. Subsequently, embryos were cultured for 3 h with 5 µg mL–1 cytochalasin B and 10 mm SrCl2 for activation and cultured for an additional 20 h in mKSOM medium. The nuclear dynamics of SCNT embryos in each donor cell group was observed using 42,6-diamidino-2-phenylindole (DAPI) staining and a fluorescent microscope at 0, 1, 7, and 24 h after nuclear injection. Data were analyzed by Student's t-test. The cell viability after thawing by trypan blue vital staining was about 20% regardless of freezing temperature. At 7 h after nuclear injection, the SCNT embryos injected with frozen bone marrow cells, regardless of freezing temperature, had more single pronuclei (67%, 54/81; P < 0.05) than SCNT embryos injected with either fresh bone marrow cells (36%, 26/73) or cumulus cells (28%, 67/236). At 24 h after nuclear injection, fewer SCNT embryos injected with bone marrow cells, either fresh or frozen, developed to the 2-cell stage (fresh: 11%, 6/56; frozen at –25�C: 21%, 5/24; frozen at –80�C: 20%, 10/49) than SCNT embryos injected with cumulus cells (58%, 185/319; P < 0.05). There was no difference in the embryonic development to the 2-cell stage among SCNT embryos injected with either fresh or frozen bone marrow cells. Further studies are required to determine whether cells frozen without cryoprotectant are capable of resulting in viable clones.

58 PRODUCTION OF CLONED BOVINE EMBRYOS DERIVED FROM AMNIOTIC CELLS OF PREGNANT COWS

Progeny tests are widely used for selection of sires for beef and dairy cattle. A less costly method might be to clone the sire candidates at their earliest developmental stage possible. To produce cloned bulls, we obtained amniotic cells as donors for nuclear transfer by transvaginal aspiration of pregnant cows. However, the collected cells may include some maternal cells. In this study, we examined collection methods to obtain only fetal cells from the collected fluid. We also examined the developmental capacity of the embryos cloned from these cells. Amniotic fluids were aspirated from pregnant cows by ultrasound-guided aspiration. We collected amniotic fluids from 27 pregnant Japanese black beef cattle (between 58 and 132 days of gestation). In Method 1, cells were recovered from the whole amniotic fluid (approximately 15 mL). In Method 2, the initial 5 mL of aspirated fluid was discarded and then the next 10 mL sample was collected. Cells were recovered from the collected fluids. The cells in the fluids were washed twice by centrifugation and then cultured in AmnioMAX™-II medium (GIBCO, Grand Island, NY, USA). After 3–4 passages, the sex of the cell lines was determined by the loop-mediated isothermal amplification (LAMP) method (Eiken Chemical Co., Ltd., Tokyo, Japan). For the cell lines that were determined as 'male' by the LAMP method we further analyzed the sex of individual cells (137–620 cells of each cell line) by fluorescent in situ hybridization (FISH) using a bovineY chromosome-specific probe (Kobayashi et al. 1998 Mol. Reprod. Dev. 51, 390–394). The percentage of male cells obtained from Methods 1 and 2 were 0–0.4% (from 4 animals) and 93.7–99.5% (from 6 animals), respectively. Then, we used confluent amniotic cells from 3 cell lines obtained by Method 2 as donor cells for nuclear transfer and examined the developmental capacity of the cloned embryos. Bovine fibroblasts cultured under serum starvation were used as a control. The cells were electrically fused (2.7 kV cm–1, 11 µs, 2 times) with enucleated bovine oocytes, and activated with a calcium ionophore and cycloheximide. They were subsequently cultured in mSOF until 168 h post-activation. The data were analyzed with Fisher's protected least-squares difference (PLSD) test following ANOVA. The rates of fusion, cleavage, and development to the blastocyst stage of the cloned embryos were the same as those of the control embryos (78% v. 81%, 75% v. 75%, and 22% v. 27%, respectively; P > 0.05). Furthermore, the rate of male blastocysts derived from the cloned embryos with the three cell lines was 95% (19/20). These results indicate that the amniotic fluids collected from pregnant cows by Method 2 contained fewer maternal cells, and that the embryos cloned from the cells developed in a manner similar to that of embryos cloned from the fibroblasts. This work was supported byWakayama Prefecture CREATE, JST.

163 SEARCH FOR GENES OF WHICH THE AMOUNTS OF TRANSCRIPTS OSCILLATE EVERY 24 h IN THE MOUSE OVARY

Perturbation of circadian rhythm is believed to be detrimental to the physiology of organs, including the mammalian ovary. However, the molecular mechanisms that are regulated by circadian rhythm in the ovary have not been identified. To identify the molecular mechanisms that are regulated by circadian rhythm and to speculate on the physiologies that are likely to be damaged by perturbation of circadian rhythm in the ovary, we searched for genes in which the amount of transcripts oscillates every 24 h in the mouse ovary. To achieve this, expression profiles of circadian genes (per1, per2, and bmal1) that code transcription-regulation factors for which transcription activities are known to oscillate every 24 h in almost all organs, and wee1, the transcription activity of which circadian genes regulate and which is known to elongate the G2 phase in the cell cycle, were analyzed in this study. Six-week-old female ICR mice were kept individually under a lighting schedule with lights on for 14 h followed by lights off for 10 h. A vaginal smear of each mouse was collected every day to determine its estrous cycle. Ovaries of 3 mice were collected continuously every 4 h over a 4-day period from the start of the light period on the day of proestrus. Total RNA was extracted from each ovary, and 500 ng each was used for cDNA synthesis. Transcripts of each gene and of tbp were quantified by real-time PCR, and the amount of the transcripts of each gene in each sample was divided by the amount of tbp transcripts. The obtained relative values in each sample were used as the representative data of the amount of transcripts of each gene. The amounts of per1, per2, and bmal1 clearly oscillated every 24 h. The maximum and minimum values of per1 and per2 were observed at 16 and 4 h, respectively, after onset of the light period each day. The maximum and minimum values of bmal1 were observed at the time of onset of the light period and at 12 h after onset of the light period each day. Averages of the maximum values of per1, per2, and bmal1 each day were significantly greater than averages of the minimum values (per1, 3.60 � 0.10 and 1.38 � 0.09; per2, 0.82 � 0.08 and 0.27 � 0.06; bmal1, 0.61 � 0.05 and 0.17 � 0.01; P < 0.05). The cyclicity in the oscillation of the amount of wee1 transcripts was weaker than that observed in circadian genes, but the average of values that were obtained from 12 to 20 h after onset of the light period each day was significantly greater than that obtained from 0 to 8 h (0.29 � 0.02 and 0.22 � 0.01; P < 0.05). Our results suggested that the cell cycle of ovarian cells is regulated in a circadian manner through wee1 transcription, which is regulated by circadian genes of which the amounts of transcripts oscillate every 24 h. Because an abnormal cell cycle seems to trigger the development of tumors or follicular cysts, perturbation of circadian rhythm may cause those ovarian diseases.

38 EFFECTS OF TRICHOSTATIN A ON DNA METHYLATION IN CLONED BOVINE EMBRYOS

Recently, the efficiency of full-term development of somatic cloned mouse embryos was significantly increased by treatment with trichostatin A (TSA), an inhibitor of histone deacetylase (Kishigami et al. 2006 Biochem. Biophys. Res. Commun. 340, 183–189; Rybouchkin et al. 2006 Biol. Reprod. 74, 1083–1089). We have shown that TSA treatment improved the rate of development of the cloned bovine embryos to the blastocyst stage (Iwamoto et al. 2007 Reprod. Fertil. Dev. 19, 142 abst). Higher levels of DNA methylation have been shown in early cloned bovine embryos than in in vitro-fertilized (IVF) embryos (Dean et al. 2001 Proc. Nat. Acad. Sci. USA 98, 13734–13738; Santos et al. Curr. Biol. 13, 1116–1121). In this study, we examined the effects of TSA on DNA methylation levels in cloned bovine embryos by immunostaining with an antibody to 5-methyl cytosine (5-MeC). Bovine fibroblasts were cultured under serum starvation (0.4% FCS) for 7 days before they were used as donor cells. The cells were electrofused with bovine enucleated matured oocytes, and activated with a calcium ionophore and cycloheximide. Atotal of 131 cloned embryos were produced. The NT embryos were exposed to 0 (control) and 50 nmTSA from the start of activation to 48 h post-activation (hpa). They were then cultured in an mSOF medium. At 60 hpa, only embryos developed to the 8-cell stage were used for assessment of DNA methylation levels. Sixteen TSA-treated, 22 non-treated, and 19 IVF embryos were immunostained with 5-MeC antibody. For quantitative analysis of the DNA methylation levels, 5-MeC signals in the fluorescent images were determined using an image analyzer system (Aqua Cosmos; Hamamatsu Photonics, Shizuoka, Japan). The data were analyzed with Tukey-Kramer post hoc test for multiple comparisons following ANOVA. Relative levels of DNA methylation of TSA-treated cloned and IVF embryos did not differ (P > 0.05), but were lower than those of non-treated cloned embryos (P < 0.05). The results indicate that TSA treatment of cloned bovine embryos leads to a reduction of DNA methylation levels of their genome. The data suggest that the TSA treatment decreased the DNA methylation levels of cloned bovine embryos to the levels of IVF embryos, resulting in improved blastocyst development of the cloned embryos.

Detection of proteolytic cleavages of diabetes-associated protein IA-2 beta in the pancreas and the brain using novel anti-IA-2 beta monoclonal antibodies

Insulinoma-associated protein (IA)-2 beta, an inactive member of the protein-tyrosine phosphatase (PTP) family, is a major autoantigen in type-1 diabetes mellitus. IA-2 beta exists mainly in a 60-kDa form, and is frequently located in the dense-core secretory vesicles of pancreatic beta cells. As IA-2 beta gene-deficient mice exhibit impaired insulin secretions, IA-2 beta is probably involved in insulin secretions. In the present study, we characterized the major forms of IA-2 beta in the brain and pancreas of normal and non-obese diabetic (NOD) mice. Novel monoclonal antibodies (mAbs) against IA-2 beta revealed that this brain protein was of multiple compositions incorporating the 60-, 64-, 67- and 71-kDa forms, which were designated as IA-2 beta 60, IA-2 beta 64, IA-2 beta 67 and IA-2 beta 71, respectively. On the contrary, only the 60-kDa isoform of IA-2 beta was expressed in the mouse pancreas and in the mouse pancreatic beta cell line, MIN6. Sequence analyses revealed that IA-2 beta 60, IA-2 beta 64 and IA-2 beta 71 (brain-derived immunoprecipitated IA-2 beta isoforms) contained alternative NH2- termini starting from Glu489, Ala464, and Ser414, respectively, while IA-2 beta 60 (an MIN6-derived immunoprecipitated IA-2 beta isoform) contained those from Glu489. Consistent with the lack of an NH2-terminal region of IA-2 beta, the isoforms were recognized by their respective mAbs characterized with different epitope regions. Furthermore, Western blotting and immunohistochemistry demonstrated that NOD mice expressed similar isoforms present in the brains and pancreatic islets of C57BL/6J, BALC/CA and ICR mice, accordingly. Taken together, these results suggest that IA-2 beta undergoes at least three distinct proteolytic cleavages.

Late-onset olfactory deficits and mitral cell loss in mice lacking prion protein with ectopic expression of Doppel

Several lines of prion protein gene (Prnp)-knockout mice such as ZrchI, ZrchII, Npu, Ngsk and Rcm0 have been generated. Of these, ZrchII, Ngsk and Rcm0 exhibit late-onset ataxia due to ectopic expression of Doppel (Dpl); a result of damage to the splicing acceptor of Prnp exon 3. Recently, we developed another line of Prnp-/- mice (Rikn), which was generated by gene targeting with more nucleotides by replacing intron 2 with the pgk-neo gene (cf. Ngsk Prnp-/- mice) and showed not only ataxia but also a lower olfactory sensitivity than the other Prnp-/- mouse line ZrchI at over 60 weeks of age. The histopathology of the elderly Rikn Prnp-/- mice showed mitral cell loss concomitantly observed with gliosis of astrocytes. Western blot analysis showed that Dpl was detected in the cerebrum, cerebellum and olfactory bulb of Rikn Prnp-/- mice, where aberrant histopathology was observed. Thus, mitral cell loss and gliosis induced by ectopic Dpl expression were probably associated with the late-onset olfactory deficits in Rikn Prnp-/- mice.

Effects of water quality on in vitro fertilization and development of bovine oocytes in protein-free medium

Examination was made of the effects of water quality in medium preparation on fertilization and early development of bovine in vitro matured (IVM) oocytes in a protein-free medium. The IVM oocytes were inseminated and cultured for 7 d in protein-free media prepared with 4 different types of water preparations: tap, deionized, twice-distilled, and purified water using the Milli-Q system (Milli-Q water). High frequencies (70 to 83%) of normal fertilization were obtained in media prepared with all types of water. However, the frequency of development to the blastocyst stage in media prepared with Milli-Q water (31 +/- 3%) was significantly higher than with the 3 other types of water (11 to 13%). Moreover, the effects of storage period of Milli-Q water on early development of bovine embryos was also examined. The frequency of development to the blastocyst stage in media prepared with Milli-Q water immediately after preparation (fresh Milli-Q water; 35 +/- 4%) was significantly higher than for Milli-Q water stored for 1 wk (18 +/- 4%) or 2 wk (18 +/- 3%). Effects of commercially available purified water on early development of bovine embryos were also examined. The frequency of development to the blastocyst stage in media prepared with Milli-Q water (33 +/- 5%) was significantly higher than for purified water purchased from 3 different suppliers (Brand A; 21 +/- 6%, Brand B; 21 +/- 2%, Brand C; 21 +/- 4%). Each water sample was analyzed by the measurement of electrical conductivity, organic compounds and/or inorganic ion and endotoxin concentrations to evaluate purity. Fresh Milli-Q water showed the lowest level of electrical conductivity and contained the lowest concentration of organic compounds. These results indicate that in vitro fertilization of bovine oocytes is not affected by the water quality in the preparation of medium; however, early development of bovine embryos is seriously affected by the purification method and the storage period of water used for medium preparation.

Home-based walking improves cardiopulmonary function and health-related QOL in community-dwelling adults

The objective of our study was to investigate the effects of a home-based walking program on physical fitness and QOL among community residents. Subjects (n = 200, mean age: 64.2 years, range: 42 - 75 years) who participated in the 32-week trial were randomly allocated to one of two groups: an exercise (E) group and a control (C) group. The E group was instructed to increase the number of steps a day that they walked and to perform aerobic walking at a target heart rate for 20 minutes or more daily, 2 or more days a week. The C group was told to continue their normal level of activity. Outcome measures were the 3-minute shuttle stamina walk test (SSWT), 30-second chair-stand test (CS-30), and SF-36. Increases in SSWT values were significantly greater in the E group than in the C group (men 24.1 m vs. 6.3 m; women 8.8 m vs. 2.4 m), as were increases in CS-30 values (men 5.9 vs. 2.6; women 4.5 vs. - 0.1). On the SF-36, the scores in the E group for vitality and mental health increased significantly. Home-based walking is considered to be an effective and feasible method to improve physical fitness and QOL among community residents.

Effect of embryonic cell cycle of nuclear donor embryos on the efficiency of nuclear transfer in Japanese black cattle

In the present study, the development in vitro and in vivo of nuclear transfer (NT) embryos reconstructed with embryonic cells (blastomeres) at the 32- to 63-cell (sixth cell cycle) and 64- to 127-cell (seventh cell cycle) stages was investigated to determine the optimum range of embryonic cell cycles for yielding the highest number of identical calves in Japanese black cattle. Rates of development to the blastocyst stage (overall efficiency) were higher in the sixth cell-cycle stage (45%) than in the seventh cell-cycle stage (12%). After the transfer of the blastocysts reconstructed with blastomeres of the sixth and seventh cell cycle-stage embryos to recipient heifers, there were no differences in the pregnancy (14/35: 40% versus 3/13: 23%, respectively) or calving rates (11/39: 28% versus 3/13: 23%, respectively). These results indicate that the highest number of identical calves would be obtained by using sixth cell cycle (32- to 63-cell)-stage embryos as nuclear donors.

Accumulation of macrophages expressing MRP8 and MRP14 in skin lesions during Leishmania major infection in BALB/c and RAG-2 knockout mice

Migration inhibitory factor-related protein 8 (MRP8) and MRP14 are expressed by myeloid cells and especially known as marker proteins of an immature and inflammatory subtype of macrophages. In this study, we immunohistochemically examined an accumulation of MRP8+ and MRP14+ macrophages in skin lesions during Leishmania major infection in susceptible BALB/c and RAG-2-/- mice. L. major infection caused the development of a nodular type of skin lesion at the infection site in mice and a massive accumulation of macrophages was observed in the lesions at four weeks after the infection. Immunohistochemical analyses showed MRP8+ and MRP14+ macrophages are predominant cell types in the skin lesions in both mouse strains. In contrast, F4/80+ cells, which correspond to mature macrophages, were rarely found in the skin lesions. These data suggest that the accumulation of inflammatory subtype of macrophages in BALB/c mice during L. major infection can be induced without acquired immune responses.

Novel single nucleotide polymorphisms in the specific protein 1 binding site of the bovine PRNP promoter in Japanese Black cattle: impairment of its promoter activity

Susceptibility to transmissible spongiform encephalopathy and different alleles of the prion protein gene (PRNP) of humans and sheep are associated. A tentative association between PRNP promoter polymorphisms and bovine spongiform encephalopathy (BSE) susceptibility has been reported in German cattle, whereas none of the known polymorphisms within the bovine PRNP-coding sequence affect BSE susceptibility. In the present study, novel single nucleotide polymorphisms located in the 5'-flanking region of bovine PRNP affecting its expression were demonstrated in Japanese Black cattle. We sequenced exon 1, and the approximately 200-bp 5'-flanking region of the PRNP translation initiation site containing the proximal promoter of PRNP was harvested. We identified 7 single nucleotide polymorphisms: -184A-->G, -141T-->C, -85T-->G, -47C-->A, -6C-->T, +17C-->T and +43C-->T. Six segregated haplotypes in the population were cloned into luciferase-expressing plasmids, transfected into N2a cells, and their reporter activities were measured 48 h after transfection. Six haplotypes showed a decreased expression level including -6C-->T in specific protein 1 binding site (p < 0.05) or -141T-->C (p < 0.01) at 48 h compared with the wild-type haplotype. These results advocate that certain polymorphisms such as specific protein 1 binding site polymorphisms in the bovine PRNP promoter region in Japanese Black cattle could influence promoter activity, suggesting that breeding cattle with such substitutions may be a useful approach in reducing BSE risk.

284 IDENTIFICATION AND CHARACTERIZATION OF THE 5′-FLANKING REGION OF THREE MOUSE MATERNAL GENES (HISTONE H1OO, NUCLEOPLASMIN 2, AND ZYGOTE ARREST 1): TRANSCRIPTIONAL ACTIVITY IN MOUSE OOCYTES

Maternal transcripts that accumulate during oocyte growth are involved in the meiotic maturation, the initiation of the first mitosis, and the later pre-implantation development. Although the conserved E-box sequences in promoter region of some maternal genes (for example, Zp3 and Gdf-9), which are important in regulating gene transcripts as binding sites of transcriptional factors, may play a role in the oocyte-specific expression in ovary, the molecular mechanism that regulates the expression of the maternal genes is still not known. In this study, we have focused on the transcriptional activity of promoter regions to clarify the molecular mechanism of transcriptional regulation of these maternal genes [Histone H1oo (H1oo), Nucleoplasmin 2 (Npm2), and Zygote arrest 1 (Zar1)]. First, we observed the expression of firefly luciferase expression vectors under promoter regions of 3 maternal genes in oocytes isolated from 10- to 12-day-old mice, which is mainly NSN-type, transcriptionally active form (Bouniol-Baly et al. 1999 Biol. Reprod. 60, 580–587). Transcriptional activities of H1oo (-3975), Npm2 (-2610), and Zar1 (-5187) promoters were detected in oocytes, the relative luciferase activities being an average of 70, 130, and 12, respectively. On the other hand, these promoter activities were not detected in embryos at the 2-cell stage. Furthermore, deletion analysis of promoter elements (E-boxes) of H1oo and Npm2 was done by microinjecting deletion constructs into oocytes. In the H1oo promoter, deletion of sequences between -3975 and -72 bp from the transcription start site resulted in one-third of the level obtained in the full H1oo (-3975) promoter. In addition, deletion of sequence -68 bp resulted in no detection of luciferase activity. These findings indicate that the putative distal promoter sequences exist at the 52-flanking region (-3975 to -759) of the H1oo gene and that the region (-314 to -68) including the E-box region (-72) may be required for high-level transcriptional activity of the H1oo promoter. In the Npm2 promoter, deletion of sequences between -2610 and -180 bp from the transcription start site resulted in one-third of the level of wild-type activity of the Npm2 (-2610) promoter. In addition, deletion of sequence -101 bp resulted in no detection of luciferase activity. These findings also indicate that 3 putative distal promoter sequences exist at the 52-flanking region (-2610 to -210) of the Npm2 gene and that the region (-210 to -101) that includes the E-box region (-180) is crucial for high-level transcriptional activity of the Npm2 promoter. In conclusion, the E-box may be a key regulatory region for the expression of two of the maternal genes (H1oo and Npm2) examined. Currently, we are attempting to identify the transcriptional factor binding sites by DNase I footprint analysis and gel mobility shift assay.

48 EFFECTS OF TRICHOSTATIN A ON DEVELOPMENT OF BOVINE SOMATIC CELL NUCLEAR TRANSFER EMBRYOS

Although cloning by somatic cell nuclear transfer (SCNT) has been achieved in various mammalian species, its efficiency has been very low (Han et al. 2003 Theriogenology 59, 33–44). Successful cloning requires conversion from differentiated donor nuclei to embryonic nuclei after transfer of the somatic nuclei into enucleated oocytes. Reprogramming of the transferred somatic nuclei must be completed by the time when normal activation of the embryonic genome occurs (Solter 2000 Nat. Rev. Genet. 1, 199–207). Recently, both full-term development and pre-implantation development of mouse SCNT embryos were significantly enhanced by treatment with trichostatin A (TSA), an inhibitor of histone deacetylase (Kishigami et al. 2006 Biochem. Biophys. Res. Commun. 340, 183–189; Rybouchkin et al. 2006 Biol. Reprod. 74, 1083–1089). The objective of this study was to investigate the effects of TSA on the development of bovine SCNT embryos. Bovine fibroblasts were cultured under serum starvation (0.4% FCS) for 7 days and then used as donor cells. The cells were electro-fused with bovine enucleated matured oocytes, and activated with a calcium ionophore and cycloheximide. They were subsequently cultured in mSOF medium until 168 h post-activation (hpa). The NT embryos were exposed to 0 (control), 5, 50, and 500 nM TSA from the start of activation to 48 hpa. Experiments were repeated 3 times, and the data were analyzed with Fisher's PLSD test following ANOVA. The cleavage rates were the same among the groups (60 to 80&percnt;; P &gt;0.05). However, the blastocyst rate of NT embryos treated with 50 nM TSA was higher than that of control embryos (40&percnt; vs. 19&percnt;, respectively; P &lt; 0.05). On the other hand, the blastocyst rate was lower with 500 nM TSA than with 5 or 50 nM TSA (7&percnt; vs. 33&percnt; or 40&percnt;; P &lt; 0.05). These data suggest that proper TSA treatment after somatic cloning improves the rate of development of bovine cloned embryos to the blastocyst stage. Further research is needed to examine whether NT embryos derived from different cell lines or types have similar susceptibility to TSA.

324 EFFECT OF AGING ON AMOUNTS OF DNA METHYLTRANSFERASE mRNA IN MOUSE SPERMATOZOA

The spermatozoon is a specially differentiated cell designed to carry a haploid male genome into an oocyte at fertilization. It recently was reported that a matured spermatozoon contains several kinds of mRNAs and these are delivered into the oocyte at fertilization (Ostermeier et al. 2004 Nature 429, 154). The physiological role of paternally derived mRNAs is not clear; however, there is a report that the DNA methyltransferase (Dnmt) mRNA level in spermatozoa from male rats exposed to ethanol was significantly reduced (Bielawski et al. 2002 Alcohl. Clin. Res. 26, 347–351). The reduction of mRNA levels of Dnmt in spermatozoa would lead to altered epigenetic modification of the genome. Because factors such as age may affect spermatozoa mRNA levels, this study evaluated the effect of individual aging on the expression levels of Dnmts during spermatogenesis. This was accomplished by determining expression levels of Dnmts in the whole testis and in spermatozoa from young and aged mice by quantitative reverse-transcription-PCR. Seven- (young) and 68- (aged) week-old C57BL/6N male mice (n = 3/group) were sacrificed by cervical dislocation and whole testes and matured spermatozoa were collected. Total RNA was extracted and purified from each sample. In this study, 5 Dnmts (Dnmt1s, Dnmt1p, Dnmt3a, Dnmt3b, and Dnmt3l) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a reference gene, were examined for expression levels in whole testis and spermatozoa using SYBR Premix Ex Taq (Takara Bio, Inc., Otsu, Shiga, Japan) and the 7300 Real-Time PCR System (Applied Biosystems, Foster City, CA, USA). Real-Time PCR runs for each Dnmt and GAPDH were repeated 3 times using different RNA batches from different individuals. The GAPDH expression level was used to normalize the expression levels of each Dnmt. Data were analyzed by Student&apos;s t-test. Relative expression levels of each Dnmt in testis from aged males compared to that of young males were 0.94, 1.15, 0.91, 1.15, and 1.14 (Dnmt1s, Dnmt1p, Dnmt3a, Dnmt3b, and Dnmt3l, respectively). There was no difference in the expression levels of the 5 Dnmts examined between testes from aged and young males. On the other hand, the relative amounts of each Dnmt mRNA in spermatozoa from aged males compared to that of young males were 0.87, 0.01, 0.54, 1.07, and 1.75 (Dnmt1s, Dnmt1p, Dnmt3a, Dnmt3b, and Dnmt3l, respectively). There was a significant reduction (P &lt; 0.05) in the amount of Dnmt1p mRNA. The reason why the amount of Dnmt1p mRNA in spermatozoa from aged male mice showed such reduction is not clear. There was no difference in the relative expression levels of Dnmt1p in testis irrespective of male age. Dnmt1p is only translated in the spermatocyte during the pachytene stage in meiosis and its physiological role is not clear. To elucidate this male, age-related reduction of the amount of Dnmt1p mRNA in spermatozoa would clarify part of physiological role of Dnmt1p. This work was supported by Wakayama Prefecture Collaboration of Regional Entities for the Advanced of Technological Excellence, Japan, and by a Grant-in-Aid for the 21st Century Center of Excellence Program of the MEXT, Japan.

Neurotoxic prion protein (PrP) fragment 106-126 requires the N-terminal half of the hydrophobic region of PrP in the PrP-deficient neuronal cell line

The cytotoxicity of aged PrP(106-126) was examined using an immortalized prion protein (PrP) gene-deficient neuronal cell line. The N-terminal half of the hydrophobic region (HR) but not the octapeptide repeat (OR) of PrP was required for aged PrP(106-126) neurotoxicity, suggesting that neurotoxic signals of aged PrP(106-126) are mediated by this region.

229 DERIVATION OF PRESUMPTIVE GONOCYTES IN VITRO FROM PRIMATE EMBRYONIC STEM CELLS

Embryonic stem cells (ESCs) of nonhuman primates are important for research into human gametogenesis, because of similarities between the embryos and fetuses of nonhuman primates and those of humans. Recently, the formation of germ cells from mouse ESCs in vitro has been reported. In this study, we established cynomolgus monkey ES (cyES) cell lines and attempted to induce their differentiation into germ cells in order to obtain further information on the development of primate germ cells by observing the transcripts of some markers reported as specific for germ cells. CyES cell lines were established using blastocysts produced by intracytoplasmic sperm injection (ICSI). For inducing superovulation, females were treated with 25 IU kg-1 pregnant mare serum gonadotropin once a day for 9 days, followed by 400 IU kg-1 hCG. Oocytes were collected at 40 h after injection of hCG. After sperm injection, embryos were cultured in mCMRL medium to the blastocyst stage. For cyES cell establishment, inner cell masses (ICMs) were isolated by immunosurgery. The ESC colonies developed at about 10 days after ICM plating, and 3 cell lines were successfully established (3/11; 27.3%). All cell lines expressed Oct3/4, SSEA-4, and ALP activity. These ESCs formed teratomas containing 3 different embryonic layers when injected into SCID mice. And the cells could be passaged over 50 times without losing their original properties. To observe in vitro gametogenesis, we attempted to induce differentiation by non-adherent conditions. When cyES cells differentiated spontaneously, the aggregated structures (i.e. embryoid bodies; EBs) accumulated vasa, the expression of which is restricted to germ cells, and some meiotic markers such as dmc1 and sycp1 that exist only in synaptonemal complexes in meiosis. The existence of these markers was also confirmed by immunocytochemistry on cryosections. Interestingly, these products expressed oct4 and nanog again at Day 16, though the expression of both genes diminished at once with onset of differentiation. In vivo, it is reported that vasa, oct4, and nanog are expressed in migrating PGCs, posibly throughout the development of germ cells into spermatocytes/oocytes. Given the results obtained with the meiotic markers, it is possible that developing germ cells such as PGCs or gonocytes could be formed in cynomolgus EBs as in previous cases with mouse or human EBs. These results demonstrate that cyES cells might contribute to putative germ cells in vitro by differentiating into EBs and could be used as a model for studying mechanisms of germ cell development. This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan Mext and by a grant for the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technology Excellence of the JST.

44 NUCLEAR TRANSFER IN CATTLE USING SOMATIC CELLS FROM FROZEN TESTICLES WITHOUT CRYOPROTECTANTS

Obtaining somatic cells from preserved organs or tissues is useful for the conservation and regeneration of genetic resources by nuclear transfer (NT). Bovine cells for NT have been obtained from cooled carcasses stored at 0�C for several days (Arat et al. 2005 Reprod. Fert. Dev. 17, 164 abst) and from fetal skin tissue cryopreserved with DMSO (Fahrudin et al. 2001 J. Vet. Med. Sci. 63, 1151–1154). However, frozen storage of organs or tissues without cryoprotectants was considered to be quite inappropriate for obtaining viable cells. We report here that viable donor cells for NT were obtained from bovine testicles after frozen storage without cryoprotectants. In the first experiment, we investigated whether viable cells can be recovered from frozen testicles castrated from Japanese Black bulls. The testicles were frozen at -80�C in a freezer for several days; then some were stored in liquid nitrogen for 10 months without cryoprotectants. Before thawing, the testicles were divided into 3 pieces, caput epididymis, cauda epididymis, and testis. Each piece was then put in saline at 42�C for quick thawing. Thawed tissues were minced into 5-mm pieces and incubated at 39�C for 2 h in DMEM containing 0.1% collagenase and 0.2% dispase. After filtration through a 250-�m nylon mesh filter, the filtrates were centrifuged at 250 � 4g for 5 min. Then precipitates were resuspended with MF-start� primary culture medium (TM Cell Research Inc., Fukui, Japan) and incubated at 38.5�C under the atmosphere of 5% CO2 in air with high humidity. After 5 days of incubation, the medium was replaced and nonadherent debris was discarded. Viable cells were obtained from the caput epididymis. These cells actively proliferated and expanded. In the next experiment, to determine whether these cells can be used for NT, the cells were electrically fused with enucleated bovine oocytes. Bovine fibroblasts taken from unfrozen ear tissue were used as controls. The NT embryos were activated by Ca-ionophore treatment, followed by treatment with cycloheximide for 6 h, and then cultured in mSOF for 168 h. NT embryos reconstructed from testicle cells did not significantly differ from NT embryos made with control cells with regard to blastocyst rates (22.1% and 20.2%), cell number of blastocysts [130 � 43 and 121 � 43 (mean � SD)], and ICM ratio (21.1% and 22.6%), respectively (ANOVA). These results suggest that somatic cells derived from bovine frozen testicles can be used for nuclear transfer. Further studies are needed to examine whether viable cells can be obtained from other frozen organs or tissues. This study was partially supported by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, JST.

50 DNA METHYLATION PROFILES OF UPSTREAM ELEMENTS OF Oct-3/4 GENE IN IN VITRO FERTILIZATION (IVF) AND SOMATIC CELL NUCLEAR-TRANSFERRED (SCNT) EMBRYOS

Cloning by adult somatic cell nuclear transfer (SCNT) has proven to be successful for the production of clones from many species (Keith 2004 Cytogenet. Genome Res. 105, 285). However, somatic cloning is currently highly inefficient. One of the reasons for this is that SCNT is believed to be associated with epigenetic errors including abnormal DNA methylation of the reconstructed embryo. The Oct-3/4 gene, a member of the POU transcription factor family, is expressed throughout the pre-implantation embryo. Abnormal expression of the Oct-3/4 gene in the nuclear-transferred embryo is either directly or indirectly caused by nuclear transfer and is suggested to be indicative of a general failure to reset the genetic program (Boiani et al. 2002 Genes Dev. 16, 1209). In this study, we investigated the DNA methylation profiles of the Oct-3/4 gene in the genome of SCNT embryos, using bisulfite sequencing analysis. Then, we observed the detailed subcellular localization of Oct-3/4 proteins in SCNT embryos using immunocytochemical (ICC) analysis. Nuclear transfer of cumulus cell nuclei was carried out as previously described (Wakayama et al. 1998 Nature 394, 369). After nuclear transfer, embryos were subsequently cultured in KSOM media to the morula and blastocyst stages. We compared the methylation profiles of 3 transcriptional control elements (distal enhancer, DE; proximal enhancer, PE; and promoter) of the upstream region of the Oct-3/4 gene with the genome of in vitro fertilization (IVF) and SCNT embryos. The methylation rate of CpG sites in the DE and promoter regions of both IVF and SCNT embryos was low at both the morula and the blastocyst stages. What&apos;s interesting is that there was a significant difference in the methylation level on CpG sites in the PE element between IVF and SCNT embryos. At the morula stage, the methylation level on CpG sites in the PE element was very low in the IVF embryo and moderately high in the SCNT embryo (0.9&percnt; and 26.3&percnt;). Conversely, at the blastocyst stage, CpG sites in the PE element showed high methylation in the IVF embryo and low methylation in the SCNT embryo (55.2&percnt; and 10.5&percnt;). CpG sites in the PE element were lightly methylated (3.0&percnt;) in the inner cell mass (ICM) of the IVF embryo. This means that the main portion of methylation in the IVF blastocyst embryo occurred at the trophectoderm (TE). On the other hand, in ICM of the SCNT embryo, the methylation level of each embryonic cell was almost the same in the whole blastocyst embryo (9.8&percnt; and 10.5&percnt;). As a result, it is highly possible that the CpG sites in the PE element of ICM were methylated as in the TE. ICC analysis revealed that some SCNT embryos showed aberrant Oct-3/4 expression in the TE. These results indicate that the methylation of CpG sites in the Oct-3/4 PE element may be related to expression of Oct-3/4 in the mouse IVF and SCNT embryos. These differences in methylation level between IVF and SCNT embryos were reflected as abnormal expressions of Oct-3/4 on SCNT embryos. This study was supported by the 21st COE Program of MEST. M.K. is a JSPS Research Fellow and supported by Grant-in Aid for Scientific Research (No. 1751132) of JSPS.

298 EFFECTS OF TRICHOSTATIN A DURING IN VITRO FERTILIZATION OF BOVINE OOCYTES ON SUBSEQUENT DEVELOPMENT, CELL NUMBER, AND ALLOCATION OF RESULTING EMBRYOS

Histone acetylation is one of the major mechanisms of epigenetic reprogramming of gamete genomes after fertilization or of transferred cell genomes after nuclear transfer to establish a totipotent state for normal development. In the fertilization of bovine oocytes, asynchronous histone acetylation occurs during pronuclear formation in the manner that modification of the paternal genome precedes that of the maternal genome (Wee et al. 2006 J. Biol. Chem. 281, 6048–6057). In the present study, the effects of trichostatin A (TSA), an inhibitor of histone deacetylase, during in vitro fertilization (IVF) of bovine oocytes on subsequent embryonic development were investigated. Cumulus-enclosed oocytes obtained from slaughterhouse ovaries were in vitro-matured (IVM) for 21 h in TCM-199 supplemented with 5% v/v FCS, 0.5 mM sodium pyruvate, 0.02 AU mL-1 FSH, and 1 �g mL-1 estradiol-17β at 39�C under 5% CO2 in air. After IVM, the oocytes were subjected to IVF with 3 � 106 mL-1 of Percoll gradient-selected sperm in a defined medium (Brackett and Oliphant 1975 Biol. Reprod. 12, 260–274) supplemented with 0 (control), 5, 50, and 500 nM TSA for 18 h. After IVF, presumptive zygotes were freed from cumulus cells and cultured in mSOF medium until 168 h post-insemination (hpi) at 39�C under 5% CO2, 5% O2, and 90% N2 with high humidity. Cleavage and blastocyst development were assessed at 48 and 168 hpi, respectively. Inner cell mass (ICM) and trophectoderm (TE) of blastocysts were differentially stained by the method of Thouas et al. (2001 Reprod. Biomed. Online 3, 25–29) to assess cell number and ICM/TE ratio. Experiments were replicated 3 times. Data are presented as means � SEM and statistically analyzed by multiple comparison with the Holm method. Rates of cleavage (0 nM: 71.0 � 7%, n = 102; 5 nM: 75.5 � 5%, n = 106; 50 nM: 68.8 � 6%, n = 105; and 500 nM: 71.7 � 4%, n = 98) and blastocyst formation (21.4 � 5%, 22.3 � 6%, 17.8 � 2%, and 18.2 � 2%, respectively) were similar among the groups. However, 500 nM TSA significantly (P &lt; 0.05) increased ICM and total cell numbers (59.8 � 4 and 143.5 � 7, respectively, n = 31) compared with the control (43.1 � 3 and 120.9 � 7, n = 31). In addition, ICM/TE ratios were higher in the 50 nM (0.81 � 0.08, n = 29) and 500 nM (0.92 � 0.2, n = 31) groups than in the control (0.59 � 0.04, P &lt; 0.05). These results suggest that TSA treatment during IVF of bovine oocytes does not affect the blastocyst rate but alters the cell numbers and their allocation to ICM and TE. Overriding epigenetic modification of the genome during fertilization may have a carryover effect on cell proliferation and differentiation in pre-implantation embryos. This study was supported by a grant from Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, JST.