scholarly journals Quantitative analysis of mitochondrial DNAs in macaque embryos reprogrammed by rabbit oocytes

Reproduction ◽  
2004 ◽  
Vol 127 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Cai-Xia Yang ◽  
Zhao-Hui Kou ◽  
Kai Wang ◽  
Yan Jiang ◽  
Wen-Wei Mao ◽  
...  
Keyword(s):  
Related Species ◽  
Nuclear Transfer ◽  
Blastocyst Stage ◽  
Cell Nuclei ◽  
Cell Stage ◽  
Closely Related Species ◽  
Copy Numbers ◽  
Mitochondrial Dnas ◽  
Morula Stage ◽  
Pcr Method

In cloned animals where somatic cell nuclei and oocytes are from the same or closely related species, the mitochondrial DNA (mtDNA) of the oocyte is dominantly inherited. However, in nuclear transfer (NT) embryos where nuclear donor and oocyte are from two distantly related species, the distribution of the mtDNA species is not known. Here we determined the levels of macaque and rabbit mtDNAs in macaque embryos reprogrammed by rabbit oocytes. Quantification using a real-time PCR method showed that both macaque and rabbit mtDNAs coexist in NT embryos at all preimplantation stages, with maternal mtDNA being dominant. Single NT embryos at the 1-cell stage immediately after fusion contained 2.6 × 104 copies of macaque mtDNA and 1.3 × 106 copies of rabbit mtDNA. Copy numbers of both mtDNA species did not change significantly from the 1-cell to the morula stages. In the single blastocyst, however, the number of rabbit mtDNA increased dramatically while macaque mtDNA decreased. The ratio of nuclear donor mtDNA to oocyte mtDNA dropped sharply from 2% at the 1-cell stage to 0.011% at the blastocyst stage. These results suggest that maternal mtDNA replicates after the morula stage.

Nuclear transplantation using bovine primordial germ cells from male fetuses

1995 ◽  
Vol 7 (5) ◽  
pp. 1217 ◽  
Author(s):  
F Delhaise ◽  
FJ Ectors ◽  
Roover R de ◽  
F Ectors ◽  
F Dessy
Keyword(s):  
Nuclear Transfer ◽  
Primordial Germ Cells ◽  
Blastocyst Stage ◽  
Cell Counting ◽  
Nuclear Transplantation ◽  
Cell Nuclei ◽  
Cell Stage ◽  
Developmental Potential ◽  
Morula Stage

The developmental potential of nuclei of bovine gonial cells was investigated by nuclear transfer. Gonial cells were collected from male fetuses at about 175 days post coitum (p.c.). They were fused with enucleated oocytes; reconstituted embryos were cultured in vitro for 7 days. Embryos reaching the compacted morula or blastocyst stage were either fixed for cell counting or transferred into recipients. Out of 115 oocyte-gonia fusions, 101 (87.8%) gave rise to cleaved embryos at Day 3 and 26 (22.6%) had reached the 8-cell stage. At Day 7, 1 (1%) developed to the morula stage and 5 (4%) reached the blastocyst stage. Three blastocysts were fixed and showed normal cell numbers (135; 90; 76 cells). Three blastocysts and one morula were transferred in four recipients; two recipients were pregnant at Day 21 but only one was positive at Day 35 p.c.; this last one aborted around Day 40 p.c. No conceptus was collected. These results indicate that gonial cell nuclei can be partially reprogrammed; they are able to develop into blastocysts and to initiate gestation. However, more experiments will be necessary to prove the nuclear totipotency of bovine gonial cells.

28 EFFECT OF TRICHOSTATIN A ON IN VITRO EMBRYO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER EMBRYOS RECONSTRUCTED FROM CAT DONOR NUCLEI AND BOVINE CYTOPLASM

2013 ◽  
Vol 25 (1) ◽  
pp. 161 ◽  
Author(s):  
M. Wittayarat ◽  
Z. Namula ◽  
V. V. Luu ◽  
L. T. K. Do ◽  
Y. Sato ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Trichostatin A ◽  
Blastocyst Stage ◽  
Domestic Cat ◽  
Cell Stage ◽  
Histone Deacetylase Inhibitor Trichostatin ◽  
Invaluable Tool ◽  
Morula Stage ◽  
Bovine Oocytes

Interspecies somatic cell nuclear transfer (iSCNT) is an invaluable tool for studying nucleus-cytoplasm interactions and may provide an alternative for cloning endangered animals whose oocytes are difficult to obtain. The developmental ability of iSCNT embryos decreases with increases in taxonomic distance between the donor and recipient species. The development of cat-bovine iSCNT embryos is reportedly blocked at the 8-cell stage (Thongphakdee et al. 2008 J. Reprod. Dev. 54, 142–147). Abnormal epigenetic reprogramming, such as DNA methylation or histone modifications, may cause low iSCNT efficiencies. The present study was conducted to evaluate the effect of the histone deacetylase inhibitor trichostatin A (TSA), previously used to enhance nuclear reprogramming following SCNT, on the developmental ability of cat iSCNT embryos using bovine oocytes matured in vitro. The matured bovine oocyte was enucleated by the glass needle and the domestic cat fetal fibroblast used as the donor nuclei was then placed into the perivitelline space adjacent to the plasma membrane of the oocyte. Couplets with bovine ooplasm were fused and activated simultaneously with a single DC pulse of 2.3 kV cm–1 for 30 µs, respectively, using an electro cell fusion generator followed by cycloheximide treatment. Reconstructed cat-bovine embryos were treated with 0, 25, 50, and 100 nM concentrations of TSA for 24 h following fusion. The percentages of embryos cleaved and embryos developed to the blastocyst stage were subjected to arc sin transformation before ANOVA. The TSA treatment at 50 nM contributed significantly higher rates of cleavage and blastocyst formation (n = 139; 84.3 and 4.6%, respectively) compared with untreated embryos (n = 187; 63.8 and 0%, respectively) and embryos treated with 100 nM TSA (n = 172; 71.4 and 0%, respectively; P < 0.05). Development to the morula stage of iSCNT embryos was observed in the TSA treatment groups, whereas no embryos developed beyond the 16-cell stage in the untreated group. In conclusion, our results indicate that TSA treatment for 24 h following fusion improves the development of iSCNT embryos. Specifically, 50 nM TSA treatment provides a beneficial effect on cleavage and development to the blastocyst stage of cat iSCNT embryos using bovine oocytes matured in vitro as recipients and domestic cat fibroblasts as donor nuclei.

43 PATTERN OF NUCLEOLI FORMATION IN RACCOON-PORCINE INTERSPECIES SOMATIC CELL NUCLEAR TRANSFER EMBRYOS

2013 ◽  
Vol 25 (1) ◽  
pp. 169
Author(s):  
Y. H. Nam ◽  
Y. Jeon ◽  
S. A. Cheong ◽  
S. S. Kwak ◽  
S. H. Hyun
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Mammalian Species ◽  
Housekeeping Genes ◽  
Blastocyst Stage ◽  
Control Group ◽  
Cell Nuclei ◽  
Cell Stage ◽  
Embryonic Genome

Recently, great focus has been on the rescue of endangered animals through somatic cell nuclear transfer (SCNT). Because it is difficult to obtain the oocytes of endangered species, interspecies SCNT (iSCNT) methods have been attempted. Numerous iSCNT embryos have shown unsuccessful development due to aberrations in expression of housekeeping genes and genes dependent on the major embryonic genome activation (EGA). In particular, aberrant EGA may cause the arrest of nucleoli formation and developmental block in embryos. According to this concept, we performed raccoon iSCNT using porcine oocytes and analyzed iSCNT embryo development pattern and formation of nucleoli. Enucleated porcine oocytes were fused with raccoon fibroblasts by electrofusion. Cleavage and blastocyst formation were evaluated under a stereomicroscope at 48 and 168 h post-activation (hpa), respectively. To confirm the formation of nucleoli, which can be detected by C23 antibody labeling in many mammalian species, C23 immunocytochemistry was performed at 48 and 72 hpa. A total of 158 iSCNT embryos were cultured; 68.5% of the raccoon iSCNT embryos were cleaved at 48 hpa (1-cell stage: 9.7%; 2-cell stage: 14.4%; 4-cell stage: 34.1%; 6-cell stage: 12.7%; 8-cell stage: 7.3%; fragmented: 21.8%). But, the embryos seen as 5- to 8-cell stage did not have the same number of nuclei as their blastomere number. When raccoon iSCNT embryos were stained by Hoechst 33342, 5- to 8-blastomere raccoon iSCNT embryos had only 4 nuclei. The raccoon iSCNT embryos did not develop past the 4-cell stage and failed to form blastocysts. In the control group, 65.2% of pig SCNT embryos were cleaved at 48 hpa (1-cell stage: 8.0%; 2-cell stage: 4.2%; 4-cell stage: 23.6%; 6-cell stage: 13.6%; 8-cell stage: 23.8%; fragmented: 26.8%), and 10.0% of pig SCNT embryos developed to blastocysts. In raccoon iSCNT embryos, raccoon nuclei failed to form nucleoli at 48 and 72 hpa. By contrast, pig SCNT embryos showed 18.8 and 87.9% nucleoli formation at 48 and 72 hpa. Our results demonstrate that 4-cell-stage embryos of raccoon-porcine hybrid embryos may be produced by SCNT methods. The pig oocytes partly supported the remodeling and reprogramming of the raccoon somatic cell nuclei, but they were unable to support nucleoli formation. Moreover, aberrant nucleoli formation caused the unsuccessful development of raccoon SCNT embryos to the blastocyst stage. This work was supported by a grant from the Next Generation BioGreen 21 program (no. PJ008121012011), Rural Development Administration, Republic of Korea.

scholarly journals 57EMBRYO DEVELOPMENT FOLLOWING INTERSPECIES NUCLEAR TRANSFER OF AFRICAN BUFFALO (SYNCERUS CAFFER), BONTEBOK (DAMALISCUS DORCUS DORCUS) AND ELAND (TAUROTRAGUS ORYX) SOMATIC CELLS INTO BOVINE CYTOPLASTS

2004 ◽  
Vol 16 (2) ◽  
pp. 150 ◽  
Author(s):  
M. Matshikiza ◽  
P. Bartels ◽  
G. Vajta ◽  
F. Olivier ◽  
T. Spies ◽  
...  
Keyword(s):  
South Africa ◽  
Nuclear Transfer ◽  
Somatic Cells ◽  
Blastocyst Stage ◽  
Critically Endangered ◽  
African Buffalo ◽  
Syncerus Caffer ◽  
Cell Stage ◽  
Wildlife Species ◽  
Interspecies Nuclear Transfer

Wildlife conservation requires traditional as well as innovative conservation strategies in order to preserve gene and species diversity. Interspecies nuclear transfer has the potential to conserve genes from critically endangered wildlife species where few or no oocytes are available from the endangered species, and where representative cell lines have been established for the wildlife population while numbers were still abundant. The purpose of this study was to investigate the developmental ability of embryos reconstructed with transfer of somatic cells from the African buffalo (Syncerus caffer), bontebok (Damaliscus dorcus dorcus) and eland (Taurotragus oryx) to enucleated domestic cattle (Bos taurus) oocytes. Skin tissue from the three wildlife species were collected by surgically removing approx. 1.0×1.0cm ear skin notches from animals immobilized with a combination of etorphine hydrochloride (M99; South Africa) and azaperone (Stressnil, South Africa). The biopsies were placed into physiological saline and transported to the laboratory at 4°C within 2h, cleaned with chlorohexidine gluconate and sliced finely in Minimal Essential Medium supplemented with 10% fetal calf serum. The resultant tissue explants were treated as previously described (Baumgarten and Harley 1995 Comp. Biochem. Physiol. 110B, 37–46) and actively growing fibroblast cultures made available for the nuclear transfer process. Nuclear transfer was performed using the HMC technique (Vajta et al., 2003 Biol. Reprod. 68, 571–578) using slaughterhouse-derived bovine oocytes. Culture was performed in SOFaaci (Vajta et al., 2003 Biol. Reprod. 68, 571–578) medium supplemented with 5% cattle serum using WOWs (Vajta et al., Mol. Reprod. Dev. 50, 185–191). Two identical replicates were made with somatic cells of each species. After successful reconstruction, 57, 42 and 48 nuclear transferred and activated buffalo, bontebok and eland embryos were cultured, respectively. All except for 2 buffalo embryos cleaved; 22 (39%) developed to or over the 8-cell stage, and 2 (3.5%) of them to the blastocyst stage. All but 3 bontebok embryos cleaved, 17 (40%) developed to or over the 8-cell stage, but none of them reached the compacted morula or blastocyst stage. Sixteen (33%) of the eland embryos developed to or over the 8-cell stage with one (2%) reaching the blastocyst stage. In conclusion, buffalo, bontebok and eland embryos developed from reconstruction using their respective somatic cells combined with bovine cytoplasts, however, in vitro developmental ability to the blastocyst stage was limited. Additional basic research that establishes the regulative mechanisms involved with early preimplantation development together with optimising nuclear transfer techniques may have the potential to one day play a role in the conservation of critically endangered wildlife species.

62 REPROGRAMMING EVENTS AND DEVELOPMENTAL COMPETENCE OF RHESUS MONKEY EMBRYOS PRODUCED BY SOMATIC CELL NUCLEAR TRANSFER

2006 ◽  
Vol 18 (2) ◽  
pp. 139 ◽  
Author(s):  
S. Mitalipov ◽  
Q. Zhou ◽  
J. Byrne ◽  
W.-Z. Ji ◽  
D. Wolf
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Formation Rate ◽  
Embryonic Stem ◽  
Developmental Competence ◽  
Lamin A ◽  
Cell Nuclei ◽  
Blastocyst Development ◽  
Morula Stage

Successful reprogramming of somatic cell nuclei after nuclear transfer requires active remodeling by factors present in the nonactivated cytoplast. High levels of maturation promoting factor (MPF) activity are associated with this remodeling process which includes nuclear envelope breakdown (NEBD), premature chromosome condensation (PCC), and spindle formation. In this study, we examined the extent of nuclear remodeling in monkey somatic cell nuclear transfer (SCNT) embryos by monitoring the dynamics of lamin A/C appearance, as detected immunocytochemically, following fusion of donor cells with recipient cytoplasts. In the control, intracytoplasmic sperm injection (ICSI) fertilized embryos, lamin A/C was readily detected at the pronuclear stage but disappeared in early cleaving embryos only to reappear by the morula stage in association with the activation of the embryonic genome. We initially documented lack or incomplete NEBD and PCC in SCNT embryos in the form of retention of lamin A/C signal emanating from the donor nucleus. This observation was consistent with premature cytoplast activation due to the manipulation procedures. SCNT embryos produced by this approach typically arrested at the morula stage. Significant modifications in nuclear transfer protocols were then employed. Optimization of procedures resulted in robust NEBD and PCC, as indicated by loss of lamin A/C signal from the donor cell. Also, significant improvement of SCNT embryo development in vitro was observed, with a markedly improved blastocyst formation rate (21%). Several different fetal and adult somatic cell types screened as nuclear donors supported blastocyst development. SCNT blastocysts displayed a pattern of Oct-4 expression similar to that of sperm fertilized counterparts, indicative of efficient nuclear reprogramming. However, no pregnancies were established following a preliminary trial of 8 embryo transfers with 48 cloned embryos. Nevertheless, our results represent a breakthrough in efforts to produce cloned monkeys and should provide the resources required for the derivation of embryonic stem cells from SCNT blastocysts.

46 EXPRESSION OF TRANSCRIPTION FACTORS SPECIFIC TO THE TROPHOBLAST LINEAGE IN MOUSE SOMATIC NUCLEAR TRANSFER EMBRYOS

2008 ◽  
Vol 20 (1) ◽  
pp. 103
Author(s):  
T. Mitani ◽  
M. Nishiwaki ◽  
M. Anzai ◽  
H. Kato ◽  
Y. Hosoi ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Real Time ◽  
Real Time Pcr ◽  
Nuclear Transfer ◽  
Ectopic Expression ◽  
Expression Level ◽  
Pcr Analysis ◽  
Cell Stage ◽  
Cdx2 Expression ◽  
Morula Stage

Somatic cell nuclear transfer (SCNT) embryos can develop at relatively high rates during the preimplantation period; however, most of these fail after implantation. Development of extraembryonic tissue is indispensable for normal embryonic development. Hence, an abnormality of trophoblast development might be a significant factor in post-implantation lethality of SCNT embryos. A transcription factor, caudal-related homeobox 2 (Cdx2), appears to be involved in the segregation of ICM and trophectoderm (TE) in preimplantation embryos (Niwa et al. 2005 Cell 123, 917–929). Both Cdx2 and Oct3/4 are expressed in all cells at the morula stage, and then Cdx2 expression becomes restricted to the TE and Oct3/4 to the ICM as the blastocyst develops. Mouse embryos deficient in Cdx2 are able to develop to normal blastocysts but die soon after implantation, probably because of defects in the TE lineage. Moreover, dysplasia of the spongiotrophoblast layer might attribute to an abnormality of Tpbpa expression in mouse SCNT embryos (Wakisaka-Saito et al. 2006 Biochem. Biophys. Res. Commun. 349, 106–114). In this study, we examined the expression profiles of transcription factors implicated in trophoblast development in mouse SCNT embryos and intracytoplasmic sperm injection (ICSI) embryos by immunohistochemistry and real-time PCR analysis. SCNT embryos were produced according to the method reported previously (Wakayama et al. 1998 Nature 394, 369–374). In brief, B6D2F1 and B6C3F1 female mice were used for the collection of recipient oocytes and donor cells, respectively. After nuclear transfer, the oocytes were activated and cultured in KSOM to the morula and blastocyst stages. Immunohistochemical analysis demonstrated that in ICSI embryos Cdx2 was only partially expressed at the 8-cell stage but completely in early morulae. In contrast, in SCNT embryos, it was absent at the 8-cell stage and appeared partially at the early morula stage. Thereafter, Cdx2 expression became restricted to the TE cells in both the ICSI and the SCNT blastocysts. However, ectopic expression of Oct3/4 was observed in the TE cells of SCNT, but not in ICSI blastocysts. Real-time PCR analysis showed that at the 8-cell stage, Cdx2 was expressed in ICSI but not in SCNT embryos. In addition, the expression level of Cdx2 in SCNT embryos at the blastocyst stage was only half that in ICSI embryos (P < 0.05). However, there was no significant difference in expression level of Oct3/4 between ICSI and SCNT embryos. Eomesodermin (Eomes) is also implicated in trophoblast development and its expression depends on Cdx2, BMP4, and FGF4. In SCNT embryos, the expression level of Eomes was also only half that in ICSI embryos. These results indicate that the delayed expression of Cdx2 in SCNT embryos may lead to the ectopic expression of Oct3/4 in blastocysts and, along with the limited expression of Cdx2 and Eomes, may contribute to disorders in the function of the trophoblast lineage for normal placental development. 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.

47 DIFFERENTIAL DEVELOPMENTAL ABILITY OF EMBRYOS CLONED FROM TISSUE-SPECIFIC STEM CELLS

2007 ◽  
Vol 19 (1) ◽  
pp. 142
Author(s):  
K. Inoue ◽  
N. Ogonuki ◽  
H. Miki ◽  
S. Noda ◽  
S. Inoue ◽  
...  
Keyword(s):  
Stem Cells ◽  
Nuclear Transfer ◽  
Embryonic Stem ◽  
Donor Cell ◽  
Fibroblast Cell ◽  
High Rate ◽  
Full Potential ◽  
Cell Nuclei ◽  
Cell Stage

Although cloning animals by somatic cell nuclear transfer is generally an inefficient process, use of appropriate donor cell types may improve the cloning outcome significantly. Among the donor cells tested so far, mouse embryonic stem cells have given the best efficiency in terms of the development of reconstructed embryos into offspring. In this study, we examined whether 2 in vitro-produced pluripotent stem cells—neural stem cells (NSCs) and mesenchymal stem cells (MSCs)—could be better nuclear donors than other differentiated cells. Embryos were reconstructed by transfer of nuclei from NSCs or MSCs with full potential for differentiation in vitro. Most (76%) of the 2-cell NCS embryos developed to the 4-cell stage; 43% implanted and 1.6% developed to term after transfer to pseudopregnant recipients. These rates were very similar to those of embryos cloned from fibroblast cell nuclei. Interestingly, in the patterns of zygotic gene expression, NSC embryos were more similar to in vitro-fertilized embryos than fibroblast cloned embryos. By contrast, embryos reconstructed using MSC nuclei showed lower developmental ability and no implantation was obtained after embryo transfer. Chromosomal analysis of the donor MSCs revealed very high frequencies of monosomy and trisomy, which might have caused the very poor post-implantation development of embryos following nuclear transfer. Thus, in vitro-produced pluripotent cells can serve as donors of nuclei for cloning mice, but may be prone to chromosomal aberrations leading to a high rate of cloned embryo death.

180 IDENTIFICATION AND QUANTIFICATION OF DIFFERENTIALLY REPRESENTED TRANSCRIPTS IN PREIMPLANTATION BOVINE EMBRYOS

2008 ◽  
Vol 20 (1) ◽  
pp. 169 ◽  
Author(s):  
C. E. McHughes ◽  
G. K. Springer ◽  
L. D. Spate ◽  
R. Li ◽  
R. J. Woods ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Nuclear Transfer ◽  
Developmental Stages ◽  
Reproductive Technologies ◽  
Blastocyst Stage ◽  
Preimplantation Embryos ◽  
Cell Stage ◽  
Production Techniques

Identification of transcripts that are present at key development stages of preimplantation embryos is critical for a better understanding of early embryogenesis. To that end, this project had two goals. The first was to characterize the relative abundance of multiple transcripts during several developmental stages, including metaphase II-stage oocytes (MPII), and 2-cell-stage (2-cell), precompact morula (PCM), and in vitro-produced blastocyst-stage (IVTBL) embryos. The second was to characterize differences in the relative abundance of transcripts present in in vivo- (IVVBL), in vitro-, and nuclear transfer-produced (NTBL) blastocysts. It was our hypothesis that the identification of differentially represented transcripts from these stages would reveal not only developmentally important genes, but also genes that might be aberrantly expressed due to embryo production techniques. Individual clusters from a large bovine EST project (http://genome.rnet.missouri.edu/Bovine/), which focused on female reproductive tissues and embryos, were compared using Fisher's exact test weighted by number of transcripts per tissue by gene (SAS PROC FREQ; SAS Institute, Inc., Cary, NC, USA). Of the 3144 transcripts that were present during embryogenesis, 125 were found to be differentially represented (P < 0.01) in at least one pairwise comparison (Table 1). Some transcripts found to increase in representation from the MPII to the 2-cell stage include protein kinases, PRKACA and CKS1, as well as the metabolism-related gene, PTTG1. These same transcripts were also found to decrease in representation from the 2-cell to the PCM stage. RPL15 (translation) and FTH1 (immune function) were both more highly represented in the PCM than in the 2-cell stage. From PCM to IVTBL, we saw an increase in RPS11, another translation-related transcript. When comparing blastocyst-stage embryos from different production techniques, several transcripts involved in energy production (e.g., COX7B and COX8A) were found to be more highly represented in the NTBL than in the IVTBL. COX8A was also more highly represented in the IVVBL than in the IVTBL. By investigating these differentially represented transcripts, we will be able to better understand the developmental implications of embryo manipulation. We may also be able to better develop reproductive technologies that lead to in vitro- and nuclear transfer-derived embryos which more closely follow a normal program of development. Table 1. Differentially represented transcripts between developmental stages

213 HOXB9 PROTEIN IS PRESENT THROUGHOUT EARLY EMBRYO DEVELOPMENT IN THE BOVINE

2013 ◽  
Vol 25 (1) ◽  
pp. 255
Author(s):  
C. Sauvegarde ◽  
D. Paul ◽  
R. Rezsohazy ◽  
I. Donnay
Keyword(s):  
Embryo Development ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Mature Oocyte ◽  
Blastocyst Stage ◽  
Early Embryo ◽  
Immature Oocyte ◽  
Cell Stage ◽  
Morula Stage ◽  
Oocyte Stage

Hox genes encode for homeodomain transcription factors well known to be involved in developmental control after gastrulation. However, the expression of some of these genes has been detected during oocyte maturation and early embryo development. An interesting expression profile has been obtained for HOXB9 in the bovine (Paul et al. 2011 Mol. Reprod. Dev. 78, 436): its relative expression increases between the immature oocyte and the zygote, further increases at the 5- to 8-cell stage to peak at the morula stage before decreasing at the blastocyst stage. The main objective of this work is to establish the HOXB9 protein profile from the immature oocyte to the blastocyst in the bovine. Bovine embryos were produced in vitro from immature oocytes obtained from slaughterhouse ovaries. Embryos were collected at the following stages: immature oocyte, mature oocyte, zygote (18 h post-insemination, hpi), 2-cell (26 hpi), 5 to 8 cell (48 hpi), 9 to 16 cell (96 hpi), morula (120 hpi), and blastocyst (180 hpi). The presence and distribution of HOXB9 proteins were detected by whole-mount immunofluorescence followed by confocal microscopy using an anti-human HOXB9 polyclonal antibody directed against a sequence showing 100% homology with the bovine protein. Its specificity to the bovine protein was controlled by Western blot on total protein extract from the bovine uterus and revealed, among a few bands of weak intensities, 2 bands of high intensity corresponding to the expected size. Oocytes or embryos were fixed and incubated overnight with rabbit anti-HOXB9 (Sigma, St. Louis, MO, USA) and mouse anti-E-cadherin (BD Biosciences, Franklin Lakes, NJ, USA) primary antibodies and then for 1 h with goat anti-rabbit Alexafluor 555 conjugated (Cell Signaling Technology, Beverly, MA, USA) and goat anti-mouse FITC-conjugated (Santa Cruz Biotechnology Inc., Santa Cruz, CA, USA) secondary antibodies. Embryos were then mounted in Vectashield containing DAPI. HOXB9 is detected from the immature oocyte to the blastocyst stage. At the immature oocyte stage, it is mainly localised in the germinal vesicle with a weak signal in the cytoplasm. At the mature oocyte stage, HOXB9 labelling is present in the cytoplasm. At the zygote stage, a stronger immunoreactivity is observed in the pronuclei than in the cytoplasm. From the 2-cell stage to the morula stage, the presence of HOXB9 is also more important in the nuclei than in the cytoplasm. HOXB9 is also observed at the blastocyst stage where it is localised in the nuclei of the trophectoderm cells, whereas an inconstant or weaker labelling is observed in the inner cell mass cells. In conclusion, we have shown for the first time the presence of the HOXB9 protein throughout early bovine embryo development. The results obtained suggest the presence of the maternal HOXB9 protein because it is already detected before the maternal to embryonic transition that occurs during the fourth cell cycle in the bovine. Finally, the pattern obtained at the blastocyst stage suggests a differential role of HOXB9 in the inner cell mass and trophectoderm cells. C. Sauvegarde holds a FRIA PhD grant from the Fonds National de la Recherche Scientifique (Belgium).

190 EXPRESSION OF GENES ASSOCIATED WITH WINGLESS-RELATED MOUSE MAMMARY TUMOUR VIRUS SIGNALING IN THE PRE-IMPLANTATION BOVINE EMBRYO

2015 ◽  
Vol 27 (1) ◽  
pp. 186
Author(s):  
P. Tribulo ◽  
J. I. Moss ◽  
P. J. Hansen
Keyword(s):  
Embryonic Development ◽  
Blastocyst Stage ◽  
Wnt Signalling ◽  
Mammary Tumour ◽  
Bovine Embryo ◽  
Cell Stage ◽  
Mouse Mammary Tumour Virus ◽  
Ct Value ◽  
Morula Stage ◽  
Canonical Wnt

Wingless-related mouse mammary tumour virus (WNT) signalling participates in early embryonic development to maintain pluripotency, controls cell–cell communication, and modulates cell polarization and migration. To gain an understanding of the regulation of WNT signalling during embryonic development, expression patterns of a variety of molecules involved in WNT signal transduction were evaluated. Specific genes were DKK1, an endogenous inhibitor of canonical WNT signalling, the WNT co-receptors LRP5 and LRP6, WNT-responsive transcription factors, LEF1 and TCF7, and two repressors of WNT-regulated genes, the bovine orthologue of GROUCHO (LOC505120) and AES. Embryos were produced in vitro from oocytes obtained from ovaries collected at a local abattoir. Following oocyte maturation, fertilization was performed with sperm pooled from three randomly selected bulls; a different pool of bulls was used for each replicate. Groups of 30 matured oocytes or embryos at the 2-cell [28–32 h post-insemination (hpi)], 3–4 cell (44–48 hpi), 5–8 cell (50–55 hpi), 9–16 cell (72–75 hpi), morula (120–123 hpi), and blastocyst (168–171 hpi) stages were collected. The zona pellucida was removed with proteinase, RNA was purified, cDNA synthesised using random hexamer primers and real-time qPCR performed. Data analysed were ΔCT values, which were calculated by subtracting the CT value of the geometric mean of the three housekeeping genes (GAPDH, YWHAZ, and SDHA) from the CT value of the sample. The relative transcript abundance was calculated as the 2ΔCT. Data were analysed by least-squares ANOVA using the Proc GLM procedure of SAS (SAS Institute Inc., Cary, NC, USA). A total of 5 replicates were analysed for each developmental stage. Results show significant effects of stage of development for each gene that ranged from P = 0.004 for LRP5 to P ≤ 0.0001 for AES, DKK1, LEF, LOC505120, LRP6, and TCF7. In all cases, expression declined as development advanced. Except for AES, lowest expression occurred at the blastocyst stage. Lowest expression for AES was at the morula stage; expression remained low at the blastocyst stage. For two genes, DKK1 and LEF1, there was no detectable expression at the blastocyst stage. The timing of decline in expression varied between genes, first occurring at the 9–16-cell stage (AES, LEF1, and LOC505120) or morula stage (DKK1, LRP5, LRP6, or TCF7). For DKK1, LEF1, and LRP6, there was also a slight increase in expression from the oocyte to two-cell stage. Results suggest that canonical WNT signalling is reduced at the morula and blastocyst stages relative to earlier stages in development. Research was supported by USDA-NIFA 2011-67015-30688.

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