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Development, Vol 113, Issue 1 295-304, Copyright © 1991 by Company of Biologists
JOURNAL ARTICLES |
TP Fleming and MJ Hay
Department of Biology, School of Biological Sciences, University of Southampton, UK.
The processes governing differential protein expression in preimplantation lineages were investigated using a monoclonal antibody recognising the tight junction polypeptide, ZO-1. ZO-1 localises to the maturing tight junction membrane domain in the polarised trophectoderm lineage from compaction (8-cell stage) onwards, ultimately forming a zonular belt around each trophectoderm cell of the blastocyst (32- to 64-cell stage). The protein is usually undetectable within the inner cell mass (ICM) although, in a minority of embryos, punctate ZO-1 sites are present on the surface of one or more ICM cells. Since ICM cells derive from the differentiative division of polarised 8- and 16-cell blastomeres, the distribution of ZO-1 following differentiative division in isolated, synchronised cell clusters of varying size, was examined. In contrast to the apical cytocortical pole, ZO-1 was found to be inherited by nonpolar (prospective ICM) as well as polar (prospective trophectoderm) daughter cells. Following division, polar cells adhere to and gradually envelop nonpolar cells. Prior to envelopment, ZO-1 localises to the boundary between the contact area and free membrane of daughter cells, irrespective of their phenotype. After envelopment, polar cells retain these ZO-1 contact sites whilst nonpolar cells lose them, in which case ZO-1 transiently appears as randomly-distributed punctate sites on the membrane before disappearing. Thus, symmetrical cell contact appears to initiate ZO-1 down-regulation in the ICM lineage. The biosynthetic level at which ZO-1 down-regulation occurs was investigated in immunosurgically isolated ICMs undergoing trophectoderm regeneration. By 6 h in culture, isolated ICMs generated a zonular network of ZO-1 at the contact area between outer cells, thereby demonstrating the reversibility of down-regulation. This assembly process was unaffected by alpha-amanitin treatment but was inhibited by cycloheximide. These results indicate that the ICM inherits and stabilises ZO-1 transcripts which can be utilised for rapid synthesis and assembly of the protein, a capacity that may have significance both in maintaining lineage integrity within the blastocyst and in the subsequent development of the ICM.
This article has been cited by other articles:
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  J. J Eckert, A. McCallum, A. Mears, M. G Rumsby, I. T Cameron, and T. P Fleming PKC signalling regulates tight junction membrane assembly in the pre-implantation mouse embryo Reproduction, June 1, 2004; 127(6): 653 - 667. [Abstract] [Full Text] [PDF]
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 B Sheth, B Moran, J. Anderson, and T. Fleming Post-translational control of occludin membrane assembly in mouse trophectoderm: a mechanism to regulate timing of tight junction biogenesis and blastocyst formation Development, January 2, 2000; 127(4): 831 - 840. [Abstract] [PDF]
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 R. Pey, C. Vial, G. Schatten, and M. Hafner Increase of intracellular Ca2+ and relocation of E-cadherin during experimental decompaction of mouse embryos PNAS, October 27, 1998; 95(22): 12977 - 12982. [Abstract] [Full Text] [PDF]
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B Sheth, I Fesenko, J. Collins, B Moran, A. Wild, J. Anderson, and T. Fleming Tight junction assembly during mouse blastocyst formation is regulated by late expression of ZO-1 alpha+ isoform Development, January 5, 1997; 124(10): 2027 - 2037. [Abstract] [PDF]
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J. Collins, J. Lorimer, D. Garrod, S. Pidsley, R. Buxton, and T. Fleming Regulation of desmocollin transcription in mouse preimplantation embryos Development, January 3, 1995; 121(3): 743 - 753. [Abstract] [PDF]
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C Gueth-Hallonet, A Santa-Maria, P Verroust, and B Maro Gp330 is specifically expressed in outer cells during epithelial differentiation in the preimplantation mouse embryo Development, January 11, 1994; 120(11): 3289 - 3299. [Abstract] [PDF]
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T. Fleming, M Hay, Q Javed, and S Citi Localisation of tight junction protein cingulin is temporally and spatially regulated during early mouse development Development, January 3, 1993; 117(3): 1135 - 1144. [Abstract] [PDF]
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Q Javed, T. Fleming, M Hay, and S Citi Tight junction protein cingulin is expressed by maternal and embryonic genomes during early mouse development Development, January 3, 1993; 117(3): 1145 - 1151. [Abstract] [PDF]
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