Nuclear transplantation in mammals: Remodelling of transplanted nuclei under the influence of maturation promoting factor

Fulka, Josef; First, N. L.; Moor, R. M.

doi:10.1002/bies.950181010

Cited by 60 publications

(31 citation statements)

References 40 publications

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“…This discrepancy may be due to the MPF activity [34]. In the present study, both an intact nuclear envelope and NEBD with PCC were observed when either serum fed or starved donor cells were introduced into MII cytoplasts.…”

Section: Discussionmentioning

confidence: 50%

Development of swamp buffalo (Bubalus bubalis) embryos after parthenogenetic activation and nuclear transfer using serum fed or starved fetal fibroblasts

et al. 2004

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-The knowledge of oocyte activation and somatic cell nuclear transfer in the swamp buffalo (Bubalus bubalis) is extremely rare. The objectives of this study were the following: (1) to investigate the various activation treatments on the parthenogenetic development of buffalo oocytes, (2) to examine the events of nuclear remodeling and in the in vitro development of cloned buffalo embryos reconstructed with serum fed or starved fetal fibroblats, and (3) to investigate the in vivo development of cloned embryos derived from serum fed or starved cells after transfer into the recipients. The rates of cleavage and blastocyst development were found to be significantly higher (P < 0.05) when the oocytes were activated by the combination treatment of calcium ionophore (A23187) or ethanol followed by 6-DMAP than those activated by electrical pulses and 6-DMAP or other single treatments. Flow cytometric analysis revealed that the percentage in the G0/G1 phase in serum starved cells was significantly (P < 0.05) higher than that in serum fed cells (88.8 ± 6.2 vs. 68.2 ± 2.6). At 1 h post fusion (hpf), most of the transferred nuclei (71%) from serum fed cells did not change in size, and the nuclear envelope remained intact, whereas 29% underwent NEBD and PCC. When serum starved cells were used, 83% of the transferred nuclei underwent NEBD and PCC whereas 17% remained intact. The nuclear swelling and pronucleus (PN) formation were observed at 2-4 and 12 h post activation (hpa), respectively. The remodeled nuclei underwent mitotic division and developed to the 2-cell stage within 18-24 hpa. Fifty-five percent of oocytes reconstructed with serum fed cells were 2PN and 45% were 1PN, whereas 79% of the embryos reconstructed from starved cells were 1PN and 21% were 2PN. The percentage of blastocyst development of the embryos derived from starved cells was higher than that from the serum fed cells (35% vs. 21%, P < 0.05). Pregnancy was detected after the transfer of cloned blastocysts into the recipients but no recipients supported the development to term. The results of this work can be used to establish effective activation protocols for buffalo oocytes which can be used during nuclear transfer experiments.buffalo / oocyte activation / nuclear transfer / nuclear remodeling / somatic cell * Corresponding author: scykt@mahidol.ac.th 66 J. Saikhun et al.

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Section: Discussionmentioning

confidence: 50%

Development of swamp buffalo (Bubalus bubalis) embryos after parthenogenetic activation and nuclear transfer using serum fed or starved fetal fibroblasts

et al. 2004

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“…For successful nuclear transfer and development of the resulting reconstructed egg, the properties of the donor nucleus have to become like those of the normal zygotic nucleus and the normal kinetics of remodeling occurs during the one-cell stage, and this appears to be the determining factor for the normal onset of gene expression (PintoCorreia et al 1995, Renard 1998. This procedure requires co-operation of the activities of cell cycle regulators (Fulka et al 1996) and maternal stores of protein (Almouzni & Wolffe 1993). It is assumed that the somatic cell nuclei are mysteriously converted to embryonic genomes, which then passively progress down the developmental path leading to a new individual.…”

Section: Discussionmentioning

confidence: 99%

NuMA distribution and microtubule configuration in rabbit oocytes and cloned embryos

Yan¹,

Huang²,

Zhu³

et al. 2006

Reproduction

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The assembly of microtubules and the distribution of NuMA were analyzed in rabbit oocytes and early cloned embryos. a-Tubulin was localized around the periphery of the germinal vesicle (GV). After germinal vesicle breakdown (GVBD), multi-arrayed microtubules were found tightly associated with the condensed chromosomes and assembled into spindles. After the enucleated oocyte was fused with a fibroblast, microtubules were observed around the introduced nucleus in most reconstructed embryos and formed a transient spindle 2-4 h post-fusion (hpf). A mass of microtubules surrounded the swollen pseudo-pronucleus 5 hpf and a normal spindle was formed 13 hpf in cloned embryos. NuMA was detected in the nucleus in germinal vesicle-stage oocytes, and it was concentrated at the spindle poles in both meiotic and mitotic metaphase. In both donor cell nucleus and enucleated oocyte cytoplasm, NuMA was not detected, while NuMA reappeared in pseudo-pronucleus as reconstructed embryo development proceeded. However, no evident NuMA staining was observed in the poles of transient spindle and first mitotic spindle in nuclear transfer eggs. These results indicate that NuMA localization and its spindle pole tethering function are different during rabbit oocyte meiosis and cloned embryo mitosis.

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Section: Discussionmentioning

confidence: 99%

“…On the other hand, as soon as fish eggs encounter with water, they are activated immediately and coupled with the subsequent decline of maturation promoting factor (MPF). The MPF is considered as a key factor for the reprogramming of donor nucleus in the nuclear transplants [22] .To examine the onset of hGH transcription, samples were taken from early-blastula stage in nuclear-transferred embryos supported by transgenic F 4 embryonic nuclei, and from 16-cell stage in nuclear-transferred embryos supported by transgenic F 4 tail-fin nuclei. It was unexpected that all the sampled embryos had turned on the transcriptional activity of hGH.…”

mentioning

confidence: 99%

The onset of foreign gene transcription in nuclear-transferred embryos of fish

Sun

Chen

Wang

et al. 2000

Sci. China Ser. C.-Life Sci.

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The transcriptional onset of hGH-transgene in fish was studied in the following three cases: the first is in MThGH-transgenic F 4 common carp (Cyprinus carpio) embryos, the second is in nuclear-transferred embryos supported by the transgenic F 4 embryonic nuclei, and the third is in nuclear-transferred embryos supported by the transgenic F 4 tail-fin nuclei. RT-PCR results show that the hGH-transgene initiates its transcriptional activity from early-gastrula stage, the early blastula stage and even 16-cell stage in the first, second and third cases, respectively. It looks like that fish egg cytoplasm could just offer a very restricted reprogramming on transcriptional activity of specific gene in differentiated cell nuclei by nuclear transplantation.Keywords: transgenic fish, nuclear transplantation, serial nuclear transplantation, transcription, reverse transcriptional PCR, reprogramming .Nuclear transplantation plays an important role in studies on developmental totipotency of cells, the interaction of cytoplasm and nucleus during embryogenesis and ontogenesis, and the molecular mechanism of nuclear reprogramming. To compare the patterns of gene transcription in normal embryos with that in nuclear-transferred embryos could provide evidence for what extent the differentiated cells could be reprogrammed to in host eggs. Gurdon et al. [1] studied in Xenopus that the expression of α-actin gene initiated from late-gastrula stage in normal embryo. When genetically marked nuclei of larval muscle cells were transplanted into wild-type enucleated eggs, the α-actin gene became transcriptionally inactive immediately. It was reactivated when the reconstructed embryos reached late-gastrula stage. In mammals, similar experiments have been done to study the changes of transcriptional activity of donor nuclei. Kanka et al. [2] found that the transcriptional activity of donor nucleus derived from 32-cell stage morula substantially decreased after 4.5 h and was completely inhibited at last 15 h after the nuclear transfer. The transcription resumed thereafter in 2-cell stage embryos and rapidly increased at 16-cell stage, reaching the transcriptional level typically as that of the 32-cell stage nuclei used for the transfer. In bovine, Lavoir et al. [3] transferred nuclei of 16-to 32-cell stages in vitro-fertilized embryos into enucleated oocytes and they found that the hnRNA production in nuclear transfer embryos was much higher than that in control in vitro-fertilized embryos at 1 to 4-cell stages. They concluded that it was because the reprogramming of the transferred nuclei was absent or incomplete that the patterns of Zhu et al. [4] initiated transgenic studies in fish and generated the "model of transgenic fish" [5] subsequently. In this model they pointed out that the transcripts of foreign gene could only be found after late-gratrula stage of embryogenesis. Recently, nuclear transplantation was performed to study the timing of foreign gene integration, and it was found that the integration started from blastula sta...

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Nuclear transplantation in mammals: Remodelling of transplanted nuclei under the influence of maturation promoting factor

Cited by 60 publications

References 40 publications

Development of swamp buffalo (Bubalus bubalis) embryos after parthenogenetic activation and nuclear transfer using serum fed or starved fetal fibroblasts

Development of swamp buffalo (Bubalus bubalis) embryos after parthenogenetic activation and nuclear transfer using serum fed or starved fetal fibroblasts

NuMA distribution and microtubule configuration in rabbit oocytes and cloned embryos

The onset of foreign gene transcription in nuclear-transferred embryos of fish

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