title: Tight junction messenger RNA expression levels in bovine embryos are dependent upon the ability to compact and in vitro culture methods.
abstract: We have established a transcription map of individual bovine embryos using semiquantitative reverse transcriptase-polymerase chain reaction to detect the levels of six marker genes involved in early embryo differentiation. The critical step of compaction during preimplantation development is often not accomplished or it takes place for only a short period in in vitro generated embryos, which may result in reduced viability. Compaction is accompanied by the assembly of intercellular tight junctions (TJs) as a barrier against the extraembryonic environment and as a prerequisite for blastocele formation. In the present study, we have related the expression of TJ gene mRNA in individual bovine embryos to their developmental stage, their competence to undergo a clear period of compaction before blastocyst formation, and their in vitro or in vivo origin. Our results indicate that embryos that showed a detectable and well-formed compaction period in vitro are of similar quality to their in vivo counterparts. Starting from the same amount of maternal message, in vivo and in vitro development differ most during the critical period of the major switch from maternal to embryonic genomic control before a dramatic increase of TJ mRNAs occurs upon blastocyst formation. Failure to compact in vitro results in significant reduction of specific transcript levels, in a manner that depends on culture conditions, which may contribute to reduced viability. We conclude that TJ mRNA expression levels are sensitive to environmental conditions that may influence the developmental potential of bovine blastocysts.
authors.affiliation: Division of Cell Sciences, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, United Kingdom.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Miller
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Eckert
authors.forename: Giovanna
authors.initials: G
authors.lastname: Lazzari
authors.forename: Veronique
authors.initials: V
authors.lastname: Duranthon-Richoux
authors.forename: Joe
authors.initials: J
authors.lastname: Sreenan
authors.forename: Dermot
authors.initials: D
authors.lastname: Morris
authors.forename: Cesare
authors.initials: C
authors.lastname: Galli
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Renard
authors.forename: Tom P
authors.initials: TP
authors.lastname: Fleming
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D002417:Cattle / Q000196:embryology*; D016922:Cellular Senescence; D004622:Embryo, Mammalian / Q000378:metabolism / Q000502:physiology; D005314:Embryonic and Fetal Development; D005260:Female; D066298:In Vitro Techniques; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000592:standards; D019108:Tight Junctions / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger