Cap-Independent mRNA Translation in Germ Cells

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Brett D. Keiper (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Cellular mRNAs in plants and animals have a 50-cap structure that is accepted as therecognition point to initiate translation by ribosomes. Consequently, it was long assumed that thetranslation initiation apparatus was built solely for a cap-dependent (CD) mechanism. Exceptions thatemerged invoke structural damage (proteolytic cleavage) to eukaryotic initiation factor 4 (eIF4) factorsthat disable cap recognition. The residual eIF4 complex is thought to be crippled, but capable ofcap-independent (CI) translation to recruit viral or death-associated mRNAs begrudgingly whencells are in great distress. However, situations where CI translation coexists with CD translationare now known. In such cases, CI translation is still a minor mechanism in the major backgroundof CD synthesis. In this review, I propose that germ cells do not fit this mold. Using observationsfrom various animal models of oogenesis and spermatogenesis, I suggest that CI translation is arobust partner to CD translation to carry out the translational control that is so prevalent in germ celldevelopment. Evidence suggests that CI translation provides surveillance of germ cell homeostasis,while CD translation governs the regulated protein synthesis that ushers these meiotic cells throughthe remarkable steps in sperm/oocyte differentiation.

Additional Information

Publication

Other

Language: English

Date: 2019

Keywords

protein synthesis; eIF4 factors; RNA-binding proteins; maternal/paternal mRNAs; meiosis; gametogenesis; apoptosis; caspase; picornavirus

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