Localisation of tight junction protein cingulin is temporally and spatially regulated during early mouse development

摘要: The molecular maturation of the tight junction in mouse early embryo has been investigated by monitoring distribution cingulin, a 140 x 10(3) M(r) peripheral (cytoplasmic) membrane constituent junction, at different stages development and experimental situations. Although formation does not begin until compaction 8-cell stage, cingulin is detectable oocytes all cleavage, factor consistent with our biochemical analysis expression (Javed et al., 1992, Development 117, 1145-1151). Using synchronised egg isolated cell clusters, we have identified three sites where localised, cytocortex, punctate cytoplasmic foci junctions themselves. Cytocortical present cumulus-oocyte contact site (both types), unfertilised fertilised eggs cleavage up to 16-cell morulae, particularly microvillous domains on outer surface (eg. apical poles compaction). Embryo manipulation experiments indicate that cortical labile dependent upon interactions therefore merely an inheritance from egg. Cingulin are evident only cells (prospective trophectoderm) 32-cell just prior cavitation, decline approx. 8 hours after cavitation initiated. appearance these insensitive cycloheximide treatment they colocalise apically derived endocytic vesicles visualised FITC-dextran, indicating represent degradation cytocortical turnover. between blastomeres usually although earlier assembly occurs minority (up 20%) specimens. sensitive identifiable 10 adhesion initiated ZO-1 protein assembles. Collectively, results (i) nonjunctional contribute (ii) appears occur progressively over least two cycles.