Temporal control of protein synthesis during spermatogenesis

Area of Science:

• Molecular Biology
• Reproductive Biology
• Genetics

Background:

• Transcription halts during germ cell differentiation, necessitating stored messenger RNAs (mRNAs) for protein synthesis.
• Regulatory elements in the 3' untranslated region (3' UTR) of mRNAs control translation, stability, and localization.
• Protamine 1 (Prm1) mRNA translation is temporally regulated during mammalian spermatogenesis via its 3' UTR.

Purpose of the Study:

• To investigate the role of Y box proteins and TARBP2 in the translational regulation of Prm1 mRNA during spermatogenesis.
• To elucidate the mechanism of translational repression and activation of stored mRNAs in germ cells.

Main Methods:

• Yeast three-hybrid system to study protein-RNA interactions.
• Analysis of Prm1 mRNA translational control element (TCE) and Y box recognition sequence (YRS).
• Generation and analysis of Tarbp2-mutant mice to assess in vivo function.

Main Results:

• Murine Y box proteins (MSY1, MSY2, MSY4) bind to the Prm1 3' UTR in a sequence-dependent manner, potentially acting as translational repressors.
• The 17-nucleotide translational control element (TCE) in the Prm1 3' UTR mediates translational repression.
• TARBP2 is essential for the proper translational activation of Prm1 and Prm2 mRNAs in spermatids, and its absence leads to sterility.

Conclusions:

• Y box proteins and TARBP2 are critical regulators of post-transcriptional gene expression during male gametogenesis.
• Dysregulation of mRNA storage and translation contributes to male infertility.
• Further research is needed to understand the communication between 3' UTR-bound proteins and the mRNA's 5' end for translational control.