Expression of connexin31 and connexin43 genes in early rat embryos

Reuss, Bernhard; Hellmann, P.; Traub, Otto; Butterweck, A.; Winterhager, Elke

doi:10.1002/(sici)1520-6408(1997)21:1<82::aid-dvg10>3.0.co;2-c

Cited by 27 publications

(25 citation statements)

References 35 publications

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“…It is possible that such embryos with altered transcript abundance survive to implantation because of the contribution of one or more additional connexin genes that are normally expressed along with connexin43 in preimplantation development. It has been reported that Cx31 serves as a compensatory channel during preimplantation development in rat [50], and we also previously showed that the abundance of transcripts for this gene can be modified by the culture environment [6].…”

Section: Discussionsupporting

confidence: 62%

Temporal Divergence in the Pattern of Messenger RNA Expression in Bovine Embryos Cultured from the Zygote to Blastocyst Stage In Vitro or In Vivo

Lonergan

Rizos

Gutiérrez-Adán³

et al. 2003

Biology of Reproduction

262

176

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The objective of this study was to examine the time during the postfertilization period that gene expression patterns in in vitro-cultured bovine embryos diverge from those of their in vivo-cultured counterparts. Presumptive bovine zygotes were produced by in vitro maturation and fertilization of immature oocytes collected from the ovaries of slaughtered animals. Approximately 20 h post insemination (hpi), zygotes were denuded and randomly divided into two groups for culture either in vitro, in synthetic oviduct fluid medium, or in vivo, in the ewe oviduct. Embryos were recovered from both systems at approximately 30 hpi (2-cell), 2 (4-cell), 3 (8-cell), 4 (16-cell), 5 (early morula), 6 (compact morula), or 7 (blastocyst) days post insemination. On recovery, they were examined for stage of development and snap frozen in liquid nitrogen for the analysis of transcript abundance using real-time polymerase chain reaction. The transcripts studied were glucose transporter 5, sarcosine oxidase, mitochondrial Mn-superoxide dismutase, connexin 43, interferon tau, insulin-like growth factor II, apoptosis regulator box-alpha and insulin-like growth factor-I receptor, most of which are known from our previous work to differ in terms of transcript abundance in blastocysts derived from culture in vitro or in vivo. The results demonstrate that the relative abundance of the transcripts studied varies throughout the preimplantation period and is strongly influenced by the culture environment. In addition, the data demonstrate that changes in transcript abundance in blastocyst stage embryos are in many cases a consequence of perturbed transcription earlier in development. Depending on the transcript, these differences may be evident by as little as 10 h of initiation of culture. Such information has implications not only for basic biology but also for human assisted reproduction in which there is a move toward culturing embryos to the blastocyst stage, necessitating prolonged culture in vitro under potentially deleterious conditions.

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Section: Discussionsupporting

confidence: 62%

Temporal Divergence in the Pattern of Messenger RNA Expression in Bovine Embryos Cultured from the Zygote to Blastocyst Stage In Vitro or In Vivo

Lonergan

Rizos

Gutiérrez-Adán³

et al. 2003

Biology of Reproduction

262

176

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“…Though staining for Cx26, Cx31 and Cx45 was lower than for Cx43, they exhibited mostly coexpression with Cx43, probably in the same gap junction plaque. These findings are again in accordance with observations in rodent blastocysts where Cx31 and Cx43 colocalize in the same gap junction plaque [13,14] although other data suggests these may not cooperate to form functional channels [33]. Indeed, staining patterns for all the connexin proteins investigated indicated lack of any obvious compartmentalisation between the two blastocyst cell populations.…”

Section: Discussionsupporting

confidence: 91%

“…In addition, the present study confirms that Cx43 is the predominant transcript as well as the predominantly expressed gap junction protein in human preimplantation embryos. Because of limited availability of human embryos we focused on those connexins identified as playing an important role in early embryonic and placental lineage development in rodents such as Cx43 and Cx45 for the embryo proper [13,15] and Cx31 for placental development [13,14]. Cx45 transcripts were detected in one third of PN and early cleavage stage embryos but not in later embryos, although the protein was expressed by blastocysts.…”

Section: Discussionmentioning

confidence: 99%

“…Unlike the mouse, Cx26 was found at both the mRNA and protein level in the rat blastocyst [7]. Of all the connexin isoforms, only Cx43 and Cx31 were abundantly expressed and both were identified in the trophectoderm as well as in the inner cell mass and were seen to co localise in the same gap junctional plaque [13,14]. Despite the expression of multiple connexin isoforms, the functional significance of heterogeneous connexin composition of plaques is still uncertain.…”

Section: Introductionmentioning

confidence: 99%

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Expression of connexins in human preimplantation embryos in vitro

Bloor

Wilson

Kibschull

et al. 2004

Reprod Biol Endocrinol

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Intercellular communication via gap junctions is required to coordinate developmental processes in the mammalian embryo. We have investigated if the connexin (Cx) isoforms known to form gap junctions in rodent preimplantation embryos are also expressed in human embryos, with the aim of identifying species differences in communication patterns in early development. Using a combination of polyA PCR and immunocytochemistry we have assessed the expression of Cx26, Cx31, Cx32, Cx40, Cx43 and Cx45 which are thought to be important in early rodent embryos. The results demonstrate that Cx31 and Cx43 are the main connexin isoforms expressed in human preimplantation embryos and that these isoforms are co-expressed in the blastocyst. Cx45 protein is expressed in the blastocyst but the protein may be translated from a generally low level of transcripts: which could only be detected in the PN to 4-cell embryos. Interestingly, Cx40, which is expressed by the extravillous trophoblast in the early human placenta, was not found to be expressed in the blastocyst trophectoderm from which this tissue develops. All of the connexin isoforms in human preimplantation embryos are also found in rodents pointing to a common regulation of these connexins in development of rodent and human early embryos and perhaps other species.

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“…This compartmentalization in connexin expression between the derivatives of the inner cell mass and the trophectoderm may maintain the different developmental programs. Apparently, Cx31 is not related to the first step in trophoblast lineage development and could serve as a compensatory channel during preimplantation development [62].…”

Section: Discussionmentioning

confidence: 94%

Bovine Embryo Culture in the Presence or Absence of Serum: Implications for Blastocyst Development, Cryotolerance, and Messenger RNA Expression1

Rizos

Gutiérrez-Adán

Pérez-Garnelo

et al. 2003

Biology of Reproduction

448

314

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We have previously shown that, while the intrinsic quality of the oocyte is the main factor affecting blastocyst yield during bovine embryo development in vitro, the main factor affecting the quality of the blastocyst is the postfertilization culture conditions. Therefore, any improvement in the quality of blastocysts produced in vitro is likely to derive from the modification of the postfertilization culture conditions. The objective of this study was to examine the effect of the presence or absence of serum and the concentration of BSA during the period of embryo culture in vitro on 1) cleavage rate, 2) the kinetics of embryo development, 3) blastocyst yield, and 4) blastocyst quality, as assessed by cryotolerance and gene expression patterns. The quantification of all gene transcripts was carried out by real-time quantitative reverse transcription-polymerase chain reaction. Bovine blastocysts from four sources were used: 1) in vitro culture in synthetic oviduct fluid (SOF) supplemented with 3 mg/ml BSA and 10% fetal calf serum (FCS), 2) in vitro culture in SOF + 3 mg/ml BSA in the absence of serum, 3) in vitro culture in SOF + 16 mg/ml BSA in the absence of serum, and 4) in vivo blastocysts. There was no difference in overall blastocyst yield at Day 9 between the groups. However, significantly more blastocysts were present by Day 6 in the presence of 10% serum (20.0%) compared with 3 mg/ml BSA (4.6%, P < 0.001) or 16 mg/ml BSA (11.6%, P < 0.01). By Day 7, however, this difference had disappeared. Following vitrification, there was no difference in survival between blastocysts produced in the presence of 16 mg/ml BSA or those produced in the presence of 10% FCS; the survival of both groups was significantly lower than the in vivo controls at all time points and in terms of hatching rate. In contrast, survival of blastocysts produced in SOF + 3 mg/ml BSA in the absence of serum was intermediate, with no difference remaining at 72 h when compared with in vivo embryos. Differences in relative mRNA abundance among the two groups of blastocysts analyzed were found for genes related to apoptosis (Bax), oxidative stress (MnSOD, CuZnSOD, and SOX), communication through gap junctions (Cx31 and Cx43), maternal recognition of pregnancy (IFN-tau), and differentiation and implantation (LIF and LR-beta). The presence of serum during the culture period resulted in a significant increase in the level of expression of MnSOD, SOX, Bax, LIF, and LR-beta. The level of expression of Cx31 and Cu/ZnSOD also tended to be increased, although the difference was not significant. In contrast, the level of expression of Cx43 and IFN-tau was decreased in the presence of serum. In conclusion, using a combination of measures of developmental competence (cleavage and blastocyst rates) and qualitative measures such as cryotolerance and relative mRNA abundance to give a more complete picture of the consequences of modifying medium composition on the embryo, we have shown that conditions of postfertilization culture, in particular, the presence o...

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Expression of connexin31 and connexin43 genes in early rat embryos

Cited by 27 publications

References 35 publications

Temporal Divergence in the Pattern of Messenger RNA Expression in Bovine Embryos Cultured from the Zygote to Blastocyst Stage In Vitro or In Vivo

Temporal Divergence in the Pattern of Messenger RNA Expression in Bovine Embryos Cultured from the Zygote to Blastocyst Stage In Vitro or In Vivo

Expression of connexins in human preimplantation embryos in vitro

Bovine Embryo Culture in the Presence or Absence of Serum: Implications for Blastocyst Development, Cryotolerance, and Messenger RNA Expression1

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