| Abstract: | Lysosomes are acidic and highly dynamic organelles that are essential for macromolecule
degradation and many other cellular functions. However, little is known about lysosomal
function during early embryogenesis. Here, we found that the number of lysosomes increased
after fertilization. Lysosomes were abundant during mouse preimplantation development
until the morula stage, but their numbers decreased slightly in blastocysts. Consistently,
the protein expression level of mature cathepsins B and D was high from the one-cell to
morula stages but low in the blastocyst stage. One-cell embryos injected with siRNAs
targeted to both lysosome-associated membrane protein 1 and 2 (LAMP1 and LAMP2) were
developmentally arrested at the two-cell stage. Pharmacological inhibition of lysosomes
also caused developmental retardation, resulting in accumulation of lipofuscin. Our
findings highlight the functional changes in lysosomes in mouse preimplantation
embryos. |
