Extra-mitochondrial localization and likely reproductive function of a female-transmitted cytochrome c oxidase subunit II protein.
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.
Chakrabarti
Rumela
R
Department of Biochemistry, State University of New York, Buffalo, New York 14214, USA. rumela.chakrabarti@gmail.com
Shepardson
Sally
S
Karmakar
Moumita
M
Trdan
Richard
R
Walker
Jennifer
J
Shandilya
Ramdas
R
Stewart
Don
D
Vijayaraghavan
Srinivasan
S
Hoeh
Walter
W
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology; D006066:Gonads / Q000378:metabolism / Q000648:ultrastructure; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism / Q000648:ultrastructure; D012098:Reproduction / Q000235:genetics / Q000502:physiology*; D012621:Seasons; D049876:Unionidae / Q000201:enzymology* / Q000378:metabolism* / Q000648:ultrastructure
D004272:DNA, Mitochondrial; C117108:cytochrome C oxidase subunit II; D003576:Electron Transport Complex IV