The cadherin catenin complex is extremely important during compaction from a morula to the blastula. Transition of early embryonic cells into a blastula differed depending on the presence or absence of calcium ions. In addition, an investigator blocked the expression of β-catenin using vivo morpholinos to detect its effect simultaneously on compaction. Which one of the following conditions will lead to the most successful transition of the morula into the blastula?
1
The blastula will continue to develop even when calcium ions are absent, since β-catenin will get activated automatically by cadherins.
2
In the absence of calcium ions, calcium ionophores will assist development even when vivo morpholinos to β-catenin are introduced.
3
Presence of calcium ions will enhance development when vivo morpholinos to cadherins have been introduced to the early embryo.
4
Presence of calcium ions are essential for activation of cadherin and β-catenin, so that actin gets mobilized and compaction ensues.