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Shin S, Matsumoto K, Amano T, Saeki K, Hosoi Y, Iritani A. 281 EXPRESSION PROFILE AND KNOCKDOWN ANALYSIS OF A FUNCTIONALLY UNKNOWN DD2-2 GENE IN MOUSE PRE-IMPLANTATION EMBRYOS. Reprod Fertil Dev 2007. [DOI: 10.1071/rdv19n1ab281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Zygotic gene activation (ZGA) starts at the G2 phase at the 1-cell stage in the mouse. However, the molecular mechanism of ZGA has not been completely elucidated. We have investigated the molecular functions of many gene clusters, DD clones obtained by differential display assays for ovulated eggs at the M II stage and 1-cell stage embryos at the G2 phase. As a result, we have identified a functionally unknown gene, whose sequence did not match a known transcript in the gene bank DD2-2 gene. Here, we report the expression profile and knockdown analysis of the DD2-2 gene in mouse pre-implantation embryos. Nucleotide sequence analysis of the DD2-2 cDNA revealed that the open reading frame of 1056 bp encodes a protein of 351 amino acids with a predicted molecular mass of 41.5 kDa. The deduced amino acid sequence indicated that DD2-2 protein might be a soluble protein without a signal peptide. We first investigated the expression profiles of DD2-2 in pre-implantation embryos by quantitative real-time PCR using an ABI PRISM 7300 Sequence Detection System (Applied Biosystems, Foster City, CA, USA). To investigate the effect of knockdown of the DD2-2 gene on the development of pre-implantation embryos, we injected pβ-act/antisenseDD2-2/IRES/EGFP into male pronuclei of embryos at 7 to 9 h after insemination (hpi) and observed the development of embryos that showed EGFP expression at 24 hpi. Real-time PCR analysis of pre-implantation embryos showed that maternal DD2-2 mRNA at a low level significantly increased up to the early 2-cell stage, and significantly decreased by the 4-cell stage and later, suggesting that DD2-2 gene specifically expresses at major ZGA. In the knockdown analysis, EGFP-positive embryos with pβ-act/antisenseDD2-2/IRES/EGFP showed a lower rate of development to the 4-cell stage and later, compared with that of EGFP-positive embryos with pβ-act/luc+/IRES/EGFP [72% (94/130) vs. 54% (71/131); P < 0.05], indicating that the knockdown of DD2-2 by antisense RNA resulted in a inhibition of pre-implantation development. In conclusion, the DD2-2 gene, a functionally unknown gene, may play an important role in pre-implantation 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.
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Mitani T, Nagai T, Masutani T, Kato H, Saeki K, Matsumoto K, Hosoi Y, Iritani A. 227 DIFFERENTIATION OF HEPATOCYTE-LIKE CELLS FROM MOUSE EMBRYONIC STEM CELLS IN A MONOLAYER CULTURE SYSTEM. Reprod Fertil Dev 2007. [DOI: 10.1071/rdv19n1ab227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Embryonic stem (ES) cells can be differentiated in vitro into a variety of cell lineages. In vitro differentiation of ES cells, therefore, provides a model system for organogenesis as well as an innovative approach for regenerative medicine. However, current in vitro hepatic differentiation systems from ES cells require embryoid body formation, and such systems achieve quite low differentiation efficacy. In this study, in order to examine a system for preparation of significant numbers of hepatocytes from ES cells, mouse ES cells were directly differentiated into hepatocyte-like cells using monolayer culture conditions, and their hepatic characteristics were examined. ES cells were cultured on gelatin-coated plates for 3 days in ES cell medium containing leukemia inhibitory factor (100 units mL-1) and retinoic acid (10-8 M). After 3 days, the cells were harvested by trypsinization and cultured on gelatin-coated plates for 5 days in ES cell medium containing acidic fibroblast growth factor (aFGF; 100 ng mL-1), FGF4 (20 ng mL-1), and human growth factor (50 ng mL-1). After 5 days, the cells were passaged on type I collagen-coated plates for 2 days in ES cell medium containing Oncostatin M (10 ng mL-1), followed by additional culture in modified William's E medium containing 5% FBS and dexamethasone (10-7 M) for 7 days. For characterizing the differentiated ES cells, the cells were examined for albumin production by immunocytochemistry, and the expression profiles of hepatic genes by RT-PCR. For analyzing their hepatic function, the cells were examined for glycogen production by PAS staining, and their metabolic activities of ammonia elimination and urea synthesis were measured. After 10 days of culture, almost all cells showed albumin production by immunofluoresence. RT-PCR analysis showed expression of various genes specific for hepatocytes, such as ALB, AFP, TTR, and HNF3�, but not HNF4α, and genes specific for matured hepatocytes, such as PEPCK, TAT, G6P, and Cyp7a1. After 11 days of culture, glycogen production was partially detected in the hepatocyte-like cells by PAS staining. Although ammonia elimination activity of hepatocyte-like cells was shown to be significantly lower than that of the primary culture of fetal hepatocytes after 24 and 48 h of treatment (P < 0.05), its metabolic activity was acquired at the level of about 40% of that of fetal hepatocytes. Hepatocyte-like cells also showed lower activity of urea synthesis than fetal hepatocytes at 6, 12, and 24 h of treatment (P < 0.05), but this activity increased thereafter and reached about 70% of that of fetal hepatocytes after 48 h of treatment. These results demonstrated that monolayer culture conditions for ES cell differentiation could provide an in vitro system to produce significant numbers of hepatocytes.
This work was supported by a Grant-in-Aid for the 21st Century Center of Excellence Program of the MEXT, Japan, and by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science.
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Ikeda S, Saeki K, Imai H, Yamada M. Abilities of cumulus and granulosa cells to enhance the developmental competence of bovine oocytes during in vitro maturation period are promoted by midkine; a possible implication of its apoptosis suppressing effects. Reproduction 2006; 132:549-57. [PMID: 17008466 DOI: 10.1530/rep.1.01066] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We previously reported that when midkine (MK), a heparin-binding growth differentiation factor was used inin vitromaturation (IVM) culture of bovine cumulus-enclosed oocytes (CEOs), their developmental competence to the blastocyst stage afterin vitrofertilization (IVF) was enhanced and the effect of MK might be mediated by its action upon mural granulosa cells and cumulus cells that closely surround the oocyte. In the present study, when denuded oocytes (DOs) were matured in IVM medium with or without MK (200 ng/ml) in the presence or absence of isolated cumulus cell masses and subjected to IVF, the enhancing effects of MK on the developmental competence of DOs to the blastocyst stage after IVF were exerted only in the presence of cumulus cells. In addition, we prepared the conditioned media of granulosa cells cultured with or without 200 ng MK/ml (CMMK+ or CMMK− respectively) and examined their effects on the IVM of DOs in terms of their developmental competence to the blastocyst stage after IVF. The supplementation of CMMK+ into IVM medium at 40% (v/v) significantly enhanced the blastocyst development compared with the no additive control and the CMMK− supplemented groups. Furthermore, the effects of MK during IVM of bovine CEOs on the cumulus cell apoptosis were investigated. CEOs were cultured up to 24 h in IVM medium without (control) or with 200 ng MK/ml. The genomic DNA was extracted from CEOs at 0, 6, 12, 18 and 24 h of IVM and subjected to ligation-mediated PCR (LM-PCR) to detect the apoptotic internucleosomal DNA fragmentation. DNA fragmentation was scarcely detected at the start of IVM, whereas it increased time-dependently as the IVM culture progressed. The degree of the fragmentation was significantly lower in the MK-treatment group compared with the control group at 18 and 24 h of IVM. The apoptosis-suppressing effect of MK on cumulus cells was further confirmedin situby using TUNEL on CEOs. In conclusion, data from the present study further confirmed that MK enhances the developmental competence of bovine oocytes via cumulus and granulosa cells. It was also demonstrated that MK suppresses the apoptosis that occurs in cumulus cells during the period of IVM of bovine CEOs. The putative soluble factor(s) from cumulus cells was suggested from the experiment using CMMK+ . MK may promote the production of such factors in part by its anti-apoptotic effects on cumulus cells.
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Sakudo A, Onodera T, Suganuma Y, Kobayashi T, Saeki K, Ikuta K. Recent Advances in Clarifying Prion Protein Functions Using Knockout Mice and Derived Cell Lines. Mini Rev Med Chem 2006; 6:589-601. [PMID: 16719834 DOI: 10.2174/138955706776876159] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Considerable information on the functions of prion protein (PrP) has been accumulated. One experimental approach is the use of PrP gene-knockout mice and derived cell lines. This approach has contributed to elucidating the functions of cellular prion protein (PrP(C)), such as its anti-oxidative and anti-apoptotic roles. This review will introduce the recent advances in prion biology made possible by the availability of these tools.
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Saeki K, Tamari T, Kasamatsu A, Iwamoto D, Kameyama S, Tatemizo A, Mitani T, Kato H, Hosoi Y, Matsumoto K, Taniguchi S, Ideta A, Urakawa M, Aoyagi Y, Iritani A. 69 RELATION OF SPATIAL GENE EXPRESSION PATTERNS IN BOVINE EMBRYOS RECONSTRUCTED WITH SOMATIC CELLS TO BLASTOCYST DEVELOPMENT. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Recently, enhanced development to full term was obtained with embryos reconstructed with bovine early G1 cells rather than with G0 cells (Kasinathan et al. 2001 Nat. Biotechnol. 19, 1176-1178; Urakawa et al. 2004 Theriogenology 62, 714-728). However, the reason why donor somatic cells at the early G1 phase are better for embryo reconstruction is unclear. In this study, we investigated the relation of spatial gene expression patterns at the 4- to 8-cell stage to blastocyst development of embryos reconstructed with early G1 cells. Bovine fibroblasts stably transfected with �-act/luc+/IRES/EGFP were used for embryo reconstruction. M phase cells were prepared as described by Urakawa et al. (2004). Early G1 cells were obtained from cultured M phase cells soon after the M phase cells divided. Quiescent cells (cultured in 0.4% serum for 7 days) were used as G0 cells for a control. The cells were electrofused with enucleated bovine oocytes matured in vitro, and activated with a calcium ionophore and cycloheximide. The reconstructed embryos were cultured until 60 hours post fusion (hpf), and zonae pellucidae of 4- to 8-cell embryos were removed by pronase. To determine gene expression, the LUC+ activity (luminescence) in the embryo blastomeres was detected with an imaging photon counter (Hamamatsu Photonics, Hamamatsu City, Shikuoka Prefecture, Japan) for 10 min. The embryos were categorized as being positive, mosaic, or negative depending on whether all, some or no blastomeres were luminescent, respectively. The embryos were cultured in mSOF medium individually until 168 hpf to assess development to the blastocyst stage. Blastocyst development of reconstructed embryos without detection of luminescence was also examined. Experiments were repeated three times, and the data were analyzed with Fisher's PLSD test following ANOVA. At 60 hpf, 75% (74/99) of embryos reconstructed with early G1 cells and 55% (46/83) of embryos with G0 cells developed to 4- to 8-cell stage embryos. The difference is significant (P < 0.05). The percentages of positive, mosaic, and negative embryos with G1 cells were 49, 35 and 16%, and blastocyst rates were 30, 11, and 0%, respectively. With G0 cells, the percentages were 32, 56, and 12%, and the blastocyst rates were 15, 4, and 0%, respectively. More positive embryos were obtained with early G1 cells than with G0 cells (P < 0.05). Blastocyst rates of the positive embryos with early G1 cells were the same as with G0 cells (P > 0.05). Blastocyst development of positive embryos was higher than that of mosaic and negative embryos in early G1 and G0 groups (P < 0.05). Without detection of luminescence, the blastocyst rates from the reconstructed embryos were 43% (35/81) and 16% (20/125) with early G1 and G0 cells, respectively (P < 0.05). These results suggest that the higher developmental capacity of embryos reconstructed with early G1 cells might be related to the appropriate spatial gene expression at the 4- to 8-cell stage.
A part of this study was supported by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.
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Matsuoka T, Sono Y, Matsumoto K, Amano T, Mizuno S, Hosoi Y, Saeki K, Iritani A. 136 FUNCTIONAL ANALYSIS OF RHOPHILIN-2 GENE IN PRE-IMPLANTATION MOUSE EMBRYO. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Zygotic gene activation (ZGA), which starts at the G2 phase at the 1-cell stage (Latham 1999), promotes the reprogramming of gene expression and is critical for the subsequent development of pre-implantation embryos. We have investigated the molecule function of many gene clusters, DD clones obtained by Differential-Display assays for ovulated eggs at the M II stage, and 1-cell embryos at the G2 phase. The differential expression of rhophilin-2 shown in DD assays was also confirmed by 3 independent real-time PCR analyses (P < 0.05). For these reasons, in this study, we focused on the rhophilin-2 gene, which regulates cytoskeletal organization (Peck et al. 2002). At first, we identified a protein that interacts with the Rhophilin-2 protein by a yeast 2-hybrid system. To confirm the interaction between Rhophilin-2 and the putative protein obtained by a yeast two-hybrid system, we used a co-immunoprecipitaion assay. We also investigated the expression profiles of rhophilin-2 and the transcripts of the identified protein in ovary and pre-implantation embryos using real-time PCR and immunofluorescence (IF) analysis. The ICR mice at 48 h after PMSG priming were primed with hCG, and ovaries were collected at 7 h after hCG priming. Pre-implantation embryos were collected at 1-cell, 2-cell, and 4-cell stages, and cDNA was produced by mRNA isolated from 10 oocytes or embryos in each group and was subjected to real-time PCR using a TaqMan Probe system (ABI). Sectioned ovaries and pre-implantation embryos were analyzed by IF analysis using antibody of Rhophilin-2 and the identified protein. This is the first report that GABA receptor-association protein (GABARAP) was identified as a protein that interacts with Rhophilin-2, as a result of using the yeast 2-hybrid system and subsequent co-immunoprecipitation assay. After fertilization, transcript levels of rhophilin-2 significantly decreased from the 1-cell stage to the 2-cell stage (P < 0.05), but transcript levels of GABARAP significantly increased from the 1-cell stage to the 2-cell stage (P < 0.05). The IF analysis revealed localization of Rhophilin-2 and GABARAP at the nucleolus of all follicle stage in the ovary. Moreover, Rhophiln-2 and GABARAP were found to be localized on the microtubules of 1-cell and 2-cell embryos, but no signal of Rhophilin-2 was detected in 4-cell embryos. These results suggest that Rhophilin-2 protein regulates the cytoskeletal organization in 1-cell to 2-cell embryos and is involved in the molecular mechanism of cell division by coupling with 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.
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Mitani T, Tanaka Y, Ozaki Y, Saeki K, Kato K, Matsumoto K, Hosoi Y, Iritani A. 138 IN VITRO CULTURE OF CD9-EXPRESSING CELLS ENRICHED BY MAGNETIC CELL SORTING FROM TESTES OF CRYPTORCHID ADULT AND PUP IN MICE. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Recently, studies on cell surface markers of spermatogonia in combination with germ cell transplantation techniques have made possible the functional analysis of germline stem cells (GS cells). The GS cells are downstream of the stem cells such as ES cells and embryonic germ cells (EG cells), which are derived from primordial germ cells (PGCs). Therefore, GS cells are expected to be useful in the production of genetically modified animals. In this study, we examined the enrichment and cultivation of mouse GS cells by magnetic cell sorting (MACS). Testicular cell suspensions were collected from C57BL/6J cryptorchid adult testes at 2 to 3 months after surgery and ICR pup (6 to 8 dpp) testes. They were digested by 0.1% collagenase followed by 0.25% trypsin with gentle shaking. Dissociated cell suspensions were filtrated through a glass-wool column followed by a Falcon cell strainer (40-�m mesh). They were then treated with biotin-conjugated anti-mouse CD9 antibody, whose antigen, CD9, is localized on the GS cell surface, followed by the streptavidin-microbeads treatment. The cell suspension was passed through a MACS-separation column. In Experiment I, MACS-treated fractions were analyzed by flow cytometry (FCM) on the rates of recovery and enrichment and their cellular characteristics. In Experiment II, CD9-positive (CD9+) cells were cultured on gelatin-coated MultiDish (176740, Nunc) with 4-5 � 105 cells/well in StemPro34-SFM supplemented with 1% fetal bovine serum, leukemia inhibitory factor, GDNF, bFGF, EGF, insulin, transferrin, putrescine, MEM vitamin solution, MEM-NEAA and some other reagents at 32�C or 37�C under 5% CO2 in air. They were examined for their proliferation and cytological changes such as CD9, �6-integrin and Oct-1 expression by immunohistochemistry. In Experiment I, MACS selection effectively enriched CD9+ cells from mouse testes. However, FCM analysis revealed that the CD9-negative (CD9-) cells partially remained in MACS-selected fraction from cryptorchid adult testes. In contrast, the CD9+ subpopulation could be successfully separated from CD9- subpopulation from pup testes. Therefore CD9+ subpopulation from pup testes was used for the following cultivation. In Experiment II, the cells proliferated in the first few days in suspension. Then they attached to the dish and formed colonies after 5 days or 3 days of culture at 32�C or 37�C, respectively. Immunohistochemical analysis showed that the cells maintained the expression of CD9 for at least 14 days, but their expression of �6-integrin gradually diminished. It was demonstrated by immunohistochemistry and FCM analysis that the cells in colonies expressed Oct-1, and its expression level was stronger in culture at 37�C than at 32�C. These findings indicate that the CD9+ cells collected from mouse pup testes have stem cell properties.
This work was supported by the Wakayama Prefecture Collaboration of Regional Entities for the Advanced Technological Excellence, JST; by a Grant-in-Aid for the 21st Century Center of Excellence Program of the MEXT, Japan; and by a Grant-in Aid for Scientific Research from the Japan Society for the Promotion of Science.
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Kato H, Kishimoto M, Mitani T, Matsumoto K, Saeki K, Hosoi Y, Iritani A. 306 ANALYSIS OF GLOBAL DNA METHYLATION IN BOVINE SPERMATOZOA. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Methylation of cytosine base in the CpG dinucleotide sequence (DNA methylation) is a major epigenetic modification of the genome and plays an important role in gene expression. Recently, global DNA methylation in genome was studied by using a restriction landmark genomic scanning (RLGS) method and/or a representational difference analysis (RDA) method. However, these methods are complicated and need to use restriction enzymes. Therefore, the information derived from those methods is restricted to the region of the DNA sequence which is able to be cleaved by restriction enzymes. In this study, to establish a simple method to estimate global DNA methylation level in bovine spermatozoa, we tried to develop the DNA methylation analyzing method by using immunostaining of 5-methylcytosine. The immunostaining method for 5-methylcytosine in this study was based on the method developed by Benchaib et al. (2003 Fertil. Steril. 80, 947-952) for human spermatozoa. Because of the species difference, we modified some treatments to apply to bovine spermatozoa. Frozen-thawed bovine spermatozoa were washed by using 30 and 45% Percoll gradient solutions. After washing, spermatozoa were treated with 0.25 dithicthreitol M (DTT) and 1% sodium dodecyl sulfate (SDS) at room temperature (RT). Then, treated spermatozoa were spread on a slide glass with Cytospin4 (30g, 5 � 104 cells/mL) and air-dried at RT. Air-dried bovine spermatozoa specimens were fixed in methanol: glacial acetic acid (3:1) solution at RT and treated with 1% Triton X and 1% SDS at RT; DNA was denatured with 6 N HCl at RT. After the denaturation, 5-methylcytosine in sperm DNA was analyzed by immunofluorescence technique with mouse anti 5-methylcytosine antibody and fluorescein isothiocyanate (FITC)-conjugated goat anti mouse IgG antibody. The total sperm DNA was counterstained with propidium iodide (PI). Stained samples were observed with a confocal laser scanning microscope and obtained images were analyzed with fluorescence image analysis software. The area that was clearly stained with PI in each sperm head was designated and measured as the area of total sperm DNA, and the number of the dots that showed FITC fluorescence within the total sperm DNA area was designated and measured as the area of 5-methylcytosine in total sperm DNA. The area measurement was performed with fixed light strength. Three bovine spermatozoa samples derived from different bulls, used daily for calf production by AI, were examined. The ratio of the mean total area of the 5-methylcytosine in sperm DNA to the mean total area of the sperm DNA was 34.1% in bull A (9.13 � 5.66 �m2, 26.75 � 5.29 �m2, n = 57), 45.2% in bull B (16.60 � 3.79 �m2, 36.74 � 5.95 �m2, n = 41) and 43.9% in bull C (14.66 � 4.27 �m2, 33.45 � 7.13 �m2, n = 22). There was significant difference in the ratio between bull A and bulls B and C (P < 0.01). More research is required to evaluate the meaning of this individual difference of DNA methylation between bulls.
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.
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Hosoi Y, Yamochi T, Kawata N, Takenoshita M, Ohta S, Matsumoto K, Saeki K, Iritani A. 39 DEVELOPMENTAL COMPETENCE OF RECONSTRUCTED EMBRYOS PRODUCED BY NUCLEAR TRANSFER BETWEEN CYNOMOLGUS MONKEY FIBROBLAST CELLS AND RABBIT OOCYTES. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Interspecies nuclear transfer has been used as an invaluable tool for studying nucleus-cytoplasm interactions and it may also be used for rescuing endangered species whose oocytes are difficult to obtain. In this study, we investigated interaction of the cynomolgus monkey cell as a nuclear donor with the rabbit oocyte as a host cytoplasm. Whole cynomolgus fibroblast cells were injected into the rabbit enucleated oocytes (cynomolgus-rabbit cloned embryos) and cultured in TCM-199 and RPMI 1640 culture media. Rabbit-rabbit cloned embryos we used as control in this study. Karyotype analyses confirmed that genetic material of blastocysts was derived from the cynomolgus donor cells at blastocyst stage. Mitochondrial constitution analysis of the cynomolgus-rabbit cloned embryos indicated that mitochondria from both donor cells and enucleated oocytes coexisted. After culture for 168 h post-nuclear transfer, all cynomolgus-rabbit cloned embryos in TCM-199 were arrested at the 8-cell stage, but some of them developed to the blastocyst stage in RPMI 1640 (11/59, 18.6%). In this experiment, the nutrition requirement in vitro and the cleavage rate at each 24 h were examined. When TCM-199 was supplemented with lactate, some of these embryos developed to the blastocyst stage (15.3%, 2/13). This means that cynomolgus-rabbit cloned embryos might be controlled by the donor nucleus even in these early developmental stages. However, the timing of cleavage of cynomolgus-rabbit cloned embryos is very similar to that of the rabbit-rabbit cloned embryos. Time of cleavage may depend on the protein accumulated in the cytoplasm. In the prolonged culture of reconstructed embryos on feeder cells, adhesion cells were observed. These cells are also very similar to the cells derived from cynomolgus embryos by the same method. Our results suggest that: (1) a cynomolgus nucleus can co-ordinate with rabbit oocyte cytoplasm in early embryo development, (2) the 8- to 16-cell stage block in the cynomolgus-rabbit cloned embryos may due to the same reason as that in the cynomolgus embryos, and (3) ooplasmic factors that control time of cleavage are highly conservative between the species.
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Amano T, Matsushita A, Kakegawa R, Matsumoto K, Saeki K, Hosoi Y, Iritani A. 118 EXPRESSION PROFILES OF CIRCADIAN CLOCK GENES IN MOUSE OOCYTES AND PRE-IMPLANTATION EMBRYOS. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Matsuo et al. reported that circadian clock genes regulate the timing of cell division in mouse regenerating liver cells (2003). Their results suggested the importance of circadian clock genes for organs or tissues for which functions are characterized by cell division, such as pre-implantation embryos. To obtain basic information on the molecular functions of circadian clock genes in pre-implantation embryos, we investigated the expression profiles of transcripts and proteins of some circadian clock genes, clock, bmal1, cry1, and per2, in mouse germinal vesicle oocytes (GV), MII oocytes (MII), and pre-implantation embryos using real-time PCR and immunocytochemistry (ICC). Germinal vesicle oocytes were collected from ICR females at 48 h after PMSG priming. The mouse at 48 h after PMSG priming was primed with hCG, and MII were collected at 15 h after hCG priming. The pre-implantation embryos were collected at 6, 12, 24, 36, 48, 60, 72, 84, and 96 h after insemination, and they corresponded to early 1-cell, late 1-cell, early 2-cell, late 2-cell, 4-cell, 8-cell, early morula, late morula, and blastocyst stages, respectively. cDNA was produced by mRNA isolated from 20 oocytes or embryos using oligo dT and was subjected to real-time PCR using a TaqMan Probe system (ABI). Three sets of 20 oocytes or embryos at each developmental stage were applied to mRNA extraction and real-time PCR analysis to ensure equal mRNA extraction efficiency between samples. The level of mRNA of each clock gene contained in 3 samples from each developmental stage was almost the same. Statistical analysis of the transcripts of each gene were done by ANOVA. Germinal vesicles, MII and embryos collected at each time point were subjected to ICC using antibodies of CLOCK, BMAL1, CRY1, and PER2. The oocytes or embryos treated with only secondary antibody did not produce any signal. All of the examined genes except per2 were expressed in oocytes and pre-implantation embryos. The transcript level of clock, bmal1, and cry1 in MII were significantly lower than those in GV (P < 0.05). After fertilization, transcript levels of clock, bmal1, and cry1 significantly decreased from early 1-cell stage to late 2-cell stage (P < 0.05). These decreased transcript levels were maintained until the blastocyst stage after the late 2-cell stage. Immunocytochemistry analysis showed the nuclear localization of CLOCK and BMAL1 in early and late 2-cell embryos and of CRY1 in early 2-cell embryos but no signals of PER2 in oocytes or pre-implantation embryos. Because mouse oocytes and 1- to 2-cell embryos are transcriptionally inert, the abundant transcripts of clock, bmal1, and cry1 in these stages seemed to indicate that they were synthesized and stored during the oocyte growth phase. Moreover, the nuclear localization of CLOCK, BMAL1, and CRY1 in the oocytes and 1- to 2-cell stage embryos suggested that some clock genes were translated and worked for oocyte maturation and early embryogenesis.
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.
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Teramura T, Kawata N, Fujinami N, Takenoshita M, Sagawa N, Matsumoto K, Saeki K, Hosoi Y, Iritani A. 207 ESTABILSHMENT OF CYNOMOLGUS MONKEY EMBRYONIC STEM CELL LINES AND CONFIRMATION OF THE POSSIBILITY FOR GERMINAL COMPETENCY. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Embryonic stem cells (ESCs) of nonhuman primate are important tools for human gametogenesis research. Generally, ESCs, embryos, and fetuses of nonhuman primates are similar to these of human. Recently, germ cell formation of mouse ESCs in vitro has been reported. In this study, we established new cynomolgus monkey ES (cyES) lines and determined germinal competency by assessing expression of mRNA markers. CyES lines were established using blastocysts produced by intracytoplasmic sperm injection (ICSI). For inducing super-ovulation, females were treated with 25 IU/kg pregnant mare serum gonadotropin (PMSG) once a day for 9 days, followed by 400 IU/kg hCG. Oocytes were collected 40 h after injection of hCG. After sperm injection, embryos were cultured in mCMRL medium to the blastocyst stage. For ES line establishment, inner cell masses (ICMs) were isolated by immunosurgery. ESC colonies emerged at about 10 days after ICM plating; three cyES cell lines were successfully obtained (3/11; 27.3%). We characterized these lines by immunocytochemistry for Oct-3/4, SSEA-3, and SSEA-4, which are diagnostic markers for primate ESCs, and by assay for alkaline phosphatase (ALP) activity. All cell lines expressed Oct-3/4, SSEA-4 and ALP activity. The previously reported SSEA-3 weak expression in cyES cells was not observed. These lines differentiated spontaneously when they were replaced in non-adherent culture (embryoid body: EB) or injected into SCID mice subcutaneously. To assess germ cell competency in vitro, we analyzed for the presence of vasa mRNA which shows a restricted expression pattern to germ cell formation, and DMC1 and SYCP1 which show specific existence on synaptonema complex in meiosis. Detection of these germ cell markers was performed by RT-PCR with total cDNA from ESCs and EBs. Nanog mRNA was detected only in ESCs. Oct-4 was detected in gonadal tissue of both sexes, ESCs, and EBs. Vasa was expressed in testis, but not in ESCs or somatic cells. Interestingly, we recognized weak expression of Vasa in Day 12-16 EBs. DMC1 and SYCP1 as meiosis markers were not detected. Because Oct-4 and Vasa mRNA are transcribed simultaneously, similar to that in the early part of gametogenesis such as the latter period of primordial germ cell (PGC) migration, PGC formation in cynomolgus EBs could occurr as in some cases of mouse or human EBs previously reported. Although detailed properties such as the functions of these Vasa-positive cells have not been confirmed, these results demonstrate that cyES cells obtained in the current study might contribute to putative germ cells in vitro by differentiating to EBs.
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.
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Baba Y, Saeki K, Onodera T, Doi K. Serological and immunohistochemical studies on porcine-serum-induced hepatic fibrosis in rats. Exp Mol Pathol 2005; 79:229-35. [PMID: 16226748 DOI: 10.1016/j.yexmp.2005.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 08/26/2005] [Indexed: 11/30/2022]
Abstract
We previously reported that the strain difference in the development of porcine-serum (PS)-induced rat hepatic fibrosis was closely related to the difference in the mode of MHC class-II-related genes expression. This study was carried out to clarify the serological and immunohistochemical changes in this hepatic fibrosis model. Six-week-old male Brown Norway (BN) and Wistar rats were injected with 0.5 ml of sterile PS twice a week for up to 8 weeks. The serum levels of PS-specific IgG1, IgG2a, and IgM were elevated more prominently in BN rats than Wistar rats. In the liver, significant increases in the numbers of PS-, OX-6 (RT1.B)-, CD4-, CD8, ED1-, and ED2-positive cells occurred earlier in BN rats than Wistar rats. At 8 weeks, deposition of PS and immunoglobulins was observed in hepatic fibrous septa and renal glomerular mesangium, and IgG1- and IgG2a-positive cells were found in the white pulp of the spleen. The present results suggest that humoral immunity probably regulated by MHC class II molecules and inflammatory cells may be involved in PS-induced hepatic fibrosis in rats.
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Nonaka T, Fujihashi M, Kita A, Saeki K, Ito S, Horikoshi K, Miki K. The crystal structure of a novel subtilisin-like alkaline serine protease, KP-43. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305091865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Sakudo A, Lee DC, Nakamura I, Taniuchi Y, Saeki K, Matsumoto Y, Itohara S, Ikuta K, Onodera T. Cell-autonomous PrP–Doppel interaction regulates apoptosis in PrP gene-deficient neuronal cells. Biochem Biophys Res Commun 2005; 333:448-54. [PMID: 15950943 DOI: 10.1016/j.bbrc.2005.05.128] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 05/19/2005] [Indexed: 11/22/2022]
Abstract
The Prnd-encoded prion protein (PrP)-like protein, Doppel (Dpl), is a homologue of Prnp-encoded PrP, and is N-glycosylated protein with glycosylphosphatidylinositol anchor like PrP. Recently, ectopic expressions of Prnp/Prnd chimeric mRNAs have been identified as the cause of late-onset ataxia observed in several lines of Prnp-knockout mice such as ZrchII, Ngsk, Rcm0, and Rikn mice. However, it remains unclear whether the toxic effect of Dpl expression is a cell-autonomous mechanism but rather reflect a systemic process of heterogeneous cell population in the brain. In this study, the cell-autonomous role of Dpl was estimated by investigating PrP-deficient cells (HpL3-4)-the SV40 large T-antigen immortalized and Rikn Prnp(-/-) mice-derived neuronal cell line expressing Prnp/Prnd chimeric mRNAs. The reverse transcription polymerase chain reaction revealed that serum deprivation did not increase Prnp/Prnd chimeric mRNAs, which in fact was translated into a small amount of Dpl in HpL3-4 cells, whereas serum deprivation induced apoptotic cell death of HpL3-4 cells. Dpl overexpression enhanced apoptotic cell death, whereas the toxic effect of Dpl on apoptotic cell death was neutralized by PrP expression. These results indicate that Dpl elicited dose-dependently toxic effects on PrP-deficient cells without affecting on PrP-expressing cells, suggesting that the PrP-Dpl interaction can regulate cell death in a cell-autonomous manner.
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Vassallo N, Herms J, Behrens C, Krebs B, Saeki K, Onodera T, Windl O, Kretzschmar HA. Activation of phosphatidylinositol 3-kinase by cellular prion protein and its role in cell survival. Biochem Biophys Res Commun 2005; 332:75-82. [PMID: 15896301 DOI: 10.1016/j.bbrc.2005.04.099] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 04/17/2005] [Indexed: 11/18/2022]
Abstract
The cellular prion protein (PrP(C)) is thought to be involved in protection against cell death, however the exact cellular mechanisms involved are still controversial. Herein we present data that strongly indicate a functional link between PrP(C) expression and phosphatidylinositol 3-kinase (PI 3-kinase) activation, a protein kinase that plays a pivotal role in cell survival. Both mouse neuroblastoma N2a cells and immortalized murine hippocampal neuronal cell lines expressing wild-type PrP(C) had significantly higher PI 3-kinase activity levels than their respective controls. Moreover, PI 3-kinase activity was found to be elevated in brain lysates from wild-type mice, as compared to prion protein-knockout mice. Recruitment of PI 3-kinase by PrP(C) was shown to contribute to cellular survival toward oxidative stress by using 3-morpholinosydnonimine (SIN-1) and serum deprivation. Moreover, both PI 3-kinase activation and cytoprotection by PrP(C) appeared to rely on copper binding to the N-terminal octapeptide of PrP(C). Thus, we propose a model in which the interaction of copper(II) with the N-terminal domain of PrP(C) enables transduction of a signal to PI 3-kinase; the latter, in turn, mediates downstream regulation of cell survival.
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91
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Hayashidani H, Hara-Kudo Y, Kinoshita S, Saeki K, Okatani AT, Nomura Y, Kumagai S. Differences in heat resistance among pathogenic Yersinia enterocolitica depended on growth temperature and serotype. J Food Prot 2005; 68:1081-2. [PMID: 15895746 DOI: 10.4315/0362-028x-68.5.1081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To gain a better understanding about the effect of growth temperature on heat resistance of Yersinia enterocolitica, we determined decimal reduction times at 60 degrees C (D60-values) for O:3; O:5,27; O:8; and O:9 strains harboring virulence plasmid coding for Yersinia outer membrane protein and experimentally virulence plasmid-deleted strains after they were grown to stationary phase at 7, 25, or 37 degrees C. Bacteria were inoculated into Trypticase soy broth and were incubated at several temperatures. D60-values of O:3; O:5,27; and O:8 strains were larger when they were grown at 37 degrees C than at 7 or 25 degrees C, despite the presence or absence of virulence plasmids. However, similar D60-values were observed in O:9 strains, despite growth at 7, 25, or 37 degrees C. The results indicate two types of Y. enterocolitica strains, growth temperature-dependent and -independent, and a Yersinia outer membrane protein that is not directly involved in growth temperature-dependent heat resistance.
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Inoue Y, Yamakawa Y, Sakudo A, Kinumi T, Nakamura Y, Matsumoto Y, Saeki K, Kamiyama T, Onodera T, Nishijima M. Infection route-independent accumulation of splenic abnormal prion protein. Jpn J Infect Dis 2005; 58:78-82. [PMID: 15858284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The accumulation kinetics of the abnormal form of prion protein (PrP(Sc)) in spleens and brains of scrapie (Obihiro-1)-infected mice at various times after intracerebral (i.c.), intraperitoneal (i.p.), or oral inoculation were studied. PrP(Sc) was first detected by Western blotting with anti-prion protein antibodies on days 70 and 116 after i.c. (3 microg) in spleens and brains, respectively. Although the amount of cerebral PrP(Sc) gradually increased to the maximum level on day 152 after i.c. inoculation, splenic PrP(Sc) established the maximum level on day 116 after i.c. inoculation then registered slight decreases up to day 152 with further incubation. The detectable levels of cerebral PrP(Sc) by Western blotting were established on day 231 or 259, whereas those of splenic PrP(Sc) were detected on day 94 or 93, after i.p. and oral infection, respectively. The splenic PrP(Sc) decreased slightly thereafter. These results indicate that splenic PrP(Sc) increased before cerebral PrP(Sc) established a detectable level in a manner independent of the inoculation route.
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Sakudo A, Lee DC, Li S, Nakamura T, Matsumoto Y, Saeki K, Itohara S, Ikuta K, Onodera T. PrP cooperates with STI1 to regulate SOD activity in PrP-deficient neuronal cell line. Biochem Biophys Res Commun 2005; 328:14-9. [PMID: 15670743 DOI: 10.1016/j.bbrc.2004.12.132] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Indexed: 11/26/2022]
Abstract
Cellular prion protein (PrP(C)) plays anti-apoptotic and anti-oxidative roles in apoptosis induced by serum deprivation in an immortalized prion protein gene (Prnp)-deficient neuronal cell line. The octapeptide repeat region (OR) and N-terminal half of the hydrophobic region (HR) of PrP(C) are indispensable for PrP(C) activity, but the mechanisms remain unclear. In the present study, elucidation of the mechanisms by which PrP(C) elicits the anti-oxidative activities was facilitated by evidence of stress-inducible protein 1 (STI1) mediating PrP(C)-dependent superoxide dismutase (SOD) activation. Immunoprecipitation revealed that PrP(C) was associated with STI1. The inhibitory peptides against PrP(C)-STI1 binding [STI1 pep.1 and PrP(113-132)] indicated toxic activity in PrP(C)-expressing cells by inhibiting SOD activity but not in Prnp(-/-) cells. Furthermore, OR and N-terminal half of the HR were required for the inhibitory effect of PrP(113-132) but not STI1 pep.1. These data are consistent with results established with a model where OR and N-terminal half of the HR mediate the action of STI1 upon cell survival and upregulation of SOD activity.
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Kasamatsu A, Saeki K, Tamari T, Shirouzu K, Taniguchi S, Mitani T, Aoyagi Y, Urakawa M, Ideta A, Matsumoto K, Hosoi Y, Iritani A. 40 CHARACTERIZATION OF EARLY G1 CELLS AS NUCLEAR DONORS FOR SOMATIC CELL CLONING IN CATTLE. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In somatic cell cloning, the cell cycle phase of the donor cells has critical impact on nuclear reprogramming and chromosomal normality of the reconstructed embryos. Recently, enhanced development to full term was obtained with embryos reconstructed with bovine fibroblasts soon after cell division (early G1 cells, Kasinathan P et al. 2001 Nat. Biotech. 19, 1176–1178; Urakawa M et al. 2004 Theriogenology 62, 714–728). In this study, to investigate the detailed cell cycle characteristics and gene expression of the early G1 cells as nuclear donors, we examined the cell proliferating and nuclear activity by detecting PCNA and Ki-67 in the cells, and the gene expression in the cells transfected with the luciferase gene. Bovine fibroblasts were transfected with chicken β-actin/firefly luciferase fusion gene (β-act/luc+), and stably transfected; cloned cells were used for cell analysis. We compared cell cycle characteristics for quiescent cells (0.4% serum for 7 days), cell doublets (early G1 cells) prepared by the “shake-off” method, and proliferating (30 to 40% confluency) cells. The presence of PCNA and Ki-67 and the incorporation of BrdU in the cells were determined by immunohistochemical analysis. The LUC+ signal (luminescence) in the cells was detected with an imaging photon counter for 10 consecutive min. Embryos reconstructed with these cells were cultured for 168 h for examination of blastocyst development. Experiments were repeated three times, and the data were analyzed with Fisher's PLSD test following ANOVA. Incorporation of BrdU was observed only in proliferating cells (24% of the cells). Neither PCNA nor Ki-67 signals were detected in the quiescent cells. PCNA was detected but Ki-67 was not detected in early G1 cells. Both PCNA and Ki-67 were detected in the proliferating cells. A strong LUC+ signal (6354 ± 673 pixels/cell) was detected in the proliferating cells, and weak signals were detected in the early G1 (2044 ± 303 pixels/cell, P < 0.05) and quiescent cells (617 ± 59 pixels/cell, P < 0.05). The rate of blastocyst development with early G1 cells was higher (45/133, 32%) than that with starved and proliferating cells (47/233, 21%, and 41/258, 14%, respectively, P < 0.05). These results indicate that early G1 cells were actively proliferating cells because of the positive PCNA signals, but their nuclei were silent because of the absence of Ki-67 signals and the weak LUC+ signals. These characteristics of the early G1 cells might enhance the development of the reconstructed embryos.
This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan MEXT, and by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.
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Shyu WC, Chen CP, Saeki K, Kubosaki A, Matusmoto Y, Onodera T, Ding DC, Chiang MF, Lee YJ, Lin SZ, Li H. Hypoglycemia enhances the expression of prion protein and heat-shock protein 70 in a mouse neuroblastoma cell line. J Neurosci Res 2005; 80:887-94. [PMID: 15884019 DOI: 10.1002/jnr.20509] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cellular prion protein (PrP(C)) expression can be regulated by heat-shock stress, and we designed the present study to determine whether hypoglycemia could affect PrP(C) expression. RT-PCR and Western blotting were used to measure the expression of PrP(C) and heat-shock protein (Hsp70) in mouse neuroblastoma (N18) cells cultured 3 hr to 3 days in media deprived of 97.5% (L) or 75% (M) of its glucose. Hypoglycemia caused a concomitant time-dependent and glucose dose-dependent increase in PrP(C) and Hsp70. In addition, hypoglycemia also increased phosphorylated c-Jun N-terminal kinase (JNK) protein levels in a time-dependent manner. The upregulation of PrP(C) and Hsp70 under hypoglycemic conditions was disrupted by the specific JNK inhibitor SP600125. It was also found from in vitro studies that hypoglycemic conditions induced higher levels of PrP(C) promoter activity in PrP(C) promoters containing a heat-shock element (HSE) than in PrP(C) promoters lacking HSE. We propose that hypoglycemia-increased PrP(C) expression might be due to JNK phosphorylation of a heat-shock transcriptional factor, which then interacts with HSE in the promoter of PrP(C).
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Sakudo A, Lee DC, Nishimura T, Li S, Tsuji S, Nakamura T, Matsumoto Y, Saeki K, Itohara S, Ikuta K, Onodera T. Octapeptide repeat region and N-terminal half of hydrophobic region of prion protein (PrP) mediate PrP-dependent activation of superoxide dismutase. Biochem Biophys Res Commun 2005; 326:600-6. [PMID: 15596141 DOI: 10.1016/j.bbrc.2004.11.092] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Indexed: 11/28/2022]
Abstract
Cellular prion protein PrP(C) contains two evolutionarily conserved domains among mammals; viz., the octapeptide repeat region (OR; amino acid residue 51-90) and the hydrophobic region (HR; amino acid residue 112-145). Accumulating evidence indicates that PrP(C) acts as an inhibitor of apoptosis and regulator of superoxide dismutase (SOD) activity. To further understand how PrP(C) activates SOD and prevents apoptosis, we provide evidence here that OR and N-terminal half of HR mediate PrP(C)-dependent SOD activation and anti-apoptotic function. Removal of the OR (amino acid residue 53-94) enhances apoptosis and decreases SOD activity. Deletion of the N-terminal half of HR (amino acids residue 95-132) abolishes its ability to activate SOD and to prevent apoptosis, whereas that of the C-terminal half of HR (amino acids residue 124-146) has little if any effect on the anti-apoptotic activity and SOD activation. These data are consistent with a model in which the anti-apoptotic and anti-oxidative function of PrP(C) is regulated by not only OR but also the N-terminal half of HR.
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Matsumoto K, Uenoyama A, Matsuoka T, Saeki K, Hosoi Y, Iritani A. 228 EXPRESSION OF zag1 IN MOUSE PRE-IMPLANTATION EMBRYOS. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Embryonic gene activation (EGA) first occurs during the second half of the mouse 1-cell embryo (Latham KE 1999 Int. Rev. Cytol. 193, 71–124). Moreover, precise regulation of EGA is considered to be essential for normal embryo development. To understand the molecular basis for the regulation of EGA, we have focused on the identification and functional characterization of genes activated at the late 1-cell stage of the mouse embryo. Recently, we have identified and isolated a novel gene, termed zag1 (zygotic activating gene 1), transcribed specifically at the EGA, using a fluoro-differential display method with oocytes and embryos at 15 h post-insemination. Messenger RNA of zag1 expressed at lower level in the oocyte than that in the embryo at 15 h post-imsemination. In this study, we investigated the potential function of zag1 by analysis of mRNA expression and protein distribution in mouse tissues and pre-implantation embryos. Nucleotide sequence analysis of zag1 cDNA revealed that the open reading frame of 1726 bps encodes a protein of 575 amino acids with a predicted molecular mass of 66 kDa. The deduced amino acid sequence indicated that zag1 protein might be a soluble protein with a bipartite nuclear targeting sequence, a NACHT NTP domain, and an APT/GTP binding site motif as a predicted functional domain. Two μg of Poly(A)+ RNA from various tissues of adult mice were subjected to Northern blot analysis using the mouse zag1 cDNA probe. We detected this gene abundantly expressed in mouse testis and ovary by approximately 2- to 3-fold compared with one in other mouse tissues (heart, liver, kidney, lung, brain, skeletal muscle, and spleen). zag1 transcript and protein, as assessed by RT-PCR and immunoblotting, respectively, were slightly present in ovulated oocytes, gradually decreased in the early 1-cell embryos, but re-expressed in the late 1-cell and early 2-cell stage embryos which coincided with the mouse EGA. Subsequent to microinjection of an expression vector encoding zag1-enhanced green fluorescent protein (EGFP), fused protein into male pronucleus of 1-cell embryos was detected in the nuclei of 2-cell embryos. These findings suggest that zag1 may be functionally associated with early embryonic development.
This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan MEXT, and by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.
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Kato H, Murakami H, Kawasumi M, Kunieda T, Okuno M, Kishimoto M, Soma M, Iwai D, Anzai M, Mitani T, Matsumoto K, Saeki K, Hosoi Y, Iritani A. 222 METHYLATION OF THE 52-UPSTREAM REGION OF THE H19 GENE IN MOUSE SOMATIC CELL, GAMETES, WILD TYPE AND ANDROGENETIC ES CELLS. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In mammals, several genes influenced by the phenomenon of genomic imprinting are critical during development. Recently, Kono et al. (2004 Nature 428, 860–864) reported the production of intact female mouse individuals that had only two haploid sets of maternal genome. They obtained these mice by combining a normal haploid maternal genome and a mutant haploid maternal genome with a 13 k base deletion in the H19 gene and its 5′-upstream region. This genomic combination resulted in the appropriate expression of the Igf2, H19, and other imprinted genes. In the mouse genome, there are four CTCF-binding sites in the 5′-upstream region of the H19 gene. The binding of CTCF to these binding sites regulates the expression of the Igf2 and H19 genes. The binding of CTCF to its binding sites is regulated by methylation of CpG sites in binding sites. In this study, as the first step to elucidate the role of the paternal genomic imprinting during development, we investigated the methylation of CpG sites in the 5′-upstream region of the H19 gene in mouse somatic cells, gametes, and two types of ES cells. Genomic DNA was isolated from BDF1 (C57BL/6N × DBA/2N) mouse's tail (male and female somatic tissue, mST and fST, respectively), spermatozoa (S), oocytes (O), and wild type and androgenetic embryonic stem cells (wtES and agES, respectively). The methylation of CpG sites was evaluated by using the bisulfite sequencing assay. There were 13 CpG sites and a CTCF-binding site in the region from −4413 to −3976 in the H19 gene relative to the transcription start site. The percentages of CpG sites in this region that were methylated were 88% (160/182), 79% (27/130), 93% (230/247), 8% (10/130), 77% (10/13) and 89% (314/351) for mST, fST, S, O, wtES, and agES, respectively. In the CTCF-binding site core motif (CCGCGTGGTGGCAG), the percentages of methylated CpG sites were 93% (26/28), 80% (16/20), 95% (36/38), 0% (0/20), 50% (1/2) and 96% (52/54) for mST, fST, S, O, wtES, and agES, respectively. The CpG sites in the sequence of agES were highly methylated similar to the finding in spermatozoa. However, an aberrant methylation pattern was observed in some clones of agES. From these results, it was concluded that the methylation of CpG sites in the genomic sequence of agES was well conserved and, therefore, agES is useful to elucidate the role of the paternal genomic imprinting during development.
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 COE Program of the Japan MEXT.
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Fujinami N, Hosoi Y, Kato H, Mitani T, Matsumoto K, Saeki K, Iritani A. 313 EFFECTS OF ETHANOL TREATMENT AFTER INTRACYTOPLASMIC SPERM INJECTION (ICSI) ON SPERM AFTER FORMATION AND THE MICROTUBULE ORGANIZATION OF BOVINE OOCYTES. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The cleavage rate of bovine embryos is very low without activation of oocytes after intracytoplasmic sperm injection (ICSI), although both male and female pronuclei are formed. We previously reported that the stimulus due to the injected sperm alone was sufficient to lower the MPF activity of bovine oocytes after ICSI, and the activation treatment of oocytes with ethanol at 4 h after ICSI served to maintain the low levels of MPF activity until the next cell cycle started (Fujinami et al. 2004 J. Reprod. Dev. 50, 171–178). These results suggested that activation treatment is necessary to improve the embryonic development after bovine ICSI. In bovine fertilization, the sperm introduces the centrosome into the oocyte. The centrosome acts as the microtubule-organizing center and microtubules are organized within the oocyte. It is reported that the sperm aster is important for the normal fertilization process. Therefore, failure of sperm aster formation possibly causes the failure of cleavage following fertilization. To investigate the reason of the low cleavage rate after bovine ICSI without artificial activation treatment, we examined sperm aster formation and the microtubule organization in bovine oocytes with or without activation treatment after ICSI. Bull spermatozoa immobilized by piezopulse was injected into bovine oocytes matured in vitro. At 4 h after ICSI, oocytes were treated with 7% ethanol in TCM199 for 5 min for activation. Oocytes were fixed at 6 and 12 h after ICSI, and the microtubule organization was examined by using specific antibodies and immunofluorescence microscopy. The cleavage rate (51% vs. 15%) and the developmental rate to the blastocyst stage (13% vs. 3%) were increased by ethanol treatment after ICSI (with or without ethanol treatment, respectively, P < 0.05). In oocytes activated with ethanol after ICSI, both the sperm aster formation rate at 6 h and the microtubule organization rate at 12 h after ICSI were significantly higher than in oocytes without activation treatment (58%, 80% vs. 12%, 26%, P < 0.05). It was reported that the sperm aster has an important role for the pronuclear movement to make the male and female pronuclei come into close apposition. From these results, it was concluded that oocyte activation after bovine ICSI promoted sperm aster formation and microtubule organization, and was effective to improve embryonic development.
This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan MEXT, and by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.
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Saeki K, Tamari T, Kasamatsu A, Shirouzu K, Taniguchi S, Matsumoto K, Hosoi Y, Iritani A. 62 RELATION OF INTENSITY OF GENE EXPRESSION IN BOVINE RECONSTRUCTED EMBRYOS TO SUBSEQUENT DEVELOPMENT. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
During embryo development, embryonic gene activation (EGA) is the first critical event. We previously showed that EGA is also critical for further development in somatic cell-cloned embryos (Saeki K et al. 2004 Reprod. Fertil. Dev. 16, 157–158 abst). To show this, we reconstructed bovine embryos with bovine somatic cells transfected with chicken β-actin/firefly luciferase fusion gene (β−act/luc+) and showed that only luminescent embryos at 60 hours post-fusion (hpf) developed to the blastocyst stage. In this study, we examined the relation between the intensity of expression of the same reporter gene in embryos reconstructed with bovine β−act/luc+ fibroblasts and their subsequent development to the blastocyst stage. Bovine fibroblasts were transfected with β−act/luc+ as described earlier (Saeki K et al. 2004 Reprod. Fertil. Dev. 16, 157–158 abst). The stably transfected and cloned cells were cultured for several passages. The cells were cultured under serum starvation (0.4% FCS) for 7 days and then used as donor cells. In vitro-matured bovine oocytes derived from slaughterhouse ovaries were enucleated at 20 h post maturation. Enucleated oocytes were electrofused with the cells, and activated with a calcium ionophore and cycloheximide. The LUC+ signal (luminescence) in the embryos was detected in medium containing 500 μg mL−1 luciferin with an imaging photon counter (ARGUS 50, Hamamatsu, Japan) for 30 consecutive min at 60 hpf. The intensity of luminescence in embryos (4- to 8-cell stage) was graded as being strong (>10 × 104 pixels/embryo), intermediate (5 to 10 × 104 pixels/embryo), weak (<5 × 104 pixels/embryo), or absent. The embryos were cultured separately until 168 hpf, and examined for blastocyst development. Experiments were repeated four times, and the data were analyzed with Fisher's PLSD test following ANOVA by Stat View software (Ver. 5.0; abacus Concepts, Berkeley, CA, USA). Of 125 embryos that were reconstructed, 74 (59%) developed to the 4- to 8-cell stage at 60 hpf. The luminescence was strong in 29 (39%) of the embryos, intermediate in 12 (16%), weak in 19 (26%), and absent in 14 (19%). Blastocysts were obtained from a group of embryos that exhibited strong luminescence (10/29, 34%), but none of the embryos from the other groups developed to blastocysts. These results suggest that active gene expression in embryos reconstructed with somatic cells is important for their subsequent development.
This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan Ministry of Education, Culture, Sports, Science, and Technology, and by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.
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