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Updated: Jun 22, 2026

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
Published on: July 19, 2021
Extra-mitochondrial localization and likely reproductive function of a female-transmitted cytochrome c oxidase
Rumela Chakrabarti1, Sally Shepardson, Moumita Karmakar
1Department of Biochemistry, State University of New York, Buffalo, New York 14214, USA. rumela.chakrabarti@gmail.com
Abstract:
Our previous study documented a reproductive function for the male-transmitted mitochondrial DNA (mtDNA)-encoded cytochrome c oxidase subunit II (MCOX2) protein in a unionoid bivalve. Here, immunoblotting, immunohistochemistry and immunoelectron microscopy analyses demonstrate that the female-transmitted protein (FCOX2) is: (i) expressed in both male and female gonads; (ii) maximally expressed in ovaries just prior to the time of the annual fertilization event; (iii) displayed in the cytoplasm and more strongly in the plasma membrane (microvilli), vitelline matrix and vitelline envelope of mature ovarian eggs; and (iv) strongly localized to the vitelline matrix of some eggs just prior to fertilization. These findings represent evidence for the extra-mitochondrial localization of an mtDNA-encoded gene product and are consistent with multifunctionality for FCOX2 in eggs.
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