Specific location of sperm mitochondria in mussel Mytilus galloprovincialis zygotes stained by MitoTracker.
In Mytilidae, mitochondrial DNA (mtDNA) in the offspring is inherited from male and female parents. Sperm mitochondria are only incorporated into the testes. This phenomenon is called doubly uniparental inheritance (DUI). Sperm mitochondria should locate in the primordial germ cell during development to maintain DUI. However, the mechanism of sperm mitochondria localization is still unknown. To reveal the mechanism, we followed the location of sperm mitochondria in Mytilus galloprovincialis zygotes fertilized with sperm stained by MitoTracker. Just after fertilization, sperm mitochondria, which were found to enter eggs from various sites, remained at sperm entry point. Five sperm mitochondria located at the male pronucleus. After pronuclear expansion, sperm mitochondria migrated to the center of the egg together with the male pronucleus. At anaphase of cleavage-I, the distribution pattern of sperm mitochondria was divided into two patterns. In pattern A, sperm mitochondria located in the equatorial region of the eggs. In pattern B, sperm mitochondria migrated and divided into two groups with chromosomes. From observations of colchicine-treated eggs, we suggest that sperm mitochondria migration from fertilization to anaphase of cleavage-I depends on the microtubules. The difference between pattern A and pattern B may be caused by whether sperm mitochondria migrated or not by the microtubules at cleavage-I.
Obata
Mayu
M
Faculty of Bioresources, Mie University, 1515, Kamihama, Tsu City, Mie Prefecture 514-8507, Japan. mayu@ztv.ne.jp
Komaru
Akira
A
D000447:Aldehydes / Q000737:chemistry; D000818:Animals; D049872:Bivalvia / Q000196:embryology*; D003078:Colchicine / Q000494:pharmacology; D005260:Female; D008297:Male; D008540:Meiosis; D008928:Mitochondria / Q000378:metabolism*; D008938:Mitosis; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000737:chemistry / Q000166:cytology*; D015053:Zygote / Q000737:chemistry / Q000166:cytology / Q000187:drug effects
D000447:Aldehydes; C111472:mitotracker green FM; D003078:Colchicine