Question

Unfertilized eggs of several animal species contain many mRNAs that should not be translated until fertilization occurs. Describe a molecular strategy employed by the egg to ensure timely activity of the proteins encoded by such mRNA.

Answer 1

Unfertilized eggs are arrested in pachytene of prophase I in meiosis. This arrest must be relieved before fertilization to enable the mitotic divisions. Exposure to some hormones and/or other proteins outcomes in breakdown of nuclear envelope enabling the meiosis to continue from prophase I. Furthermore, those proteins activate some posttranscriptional modifications of mRNA, such as polyadenylation, permitting the translation of the mRNA.