The chromatoid body in spermatogenesis.
All germ cells throughout the animal kingdom contain cytoplasmic cloud-like accumulations of material called nuage. Polar bodies in Drosophila oocytes are probably the best known forms of nuage. In spermatogenic cells, the nuage is called chromatoid body (CB). In early spermatids of the rat, it has a diameter of 1-1.5 microm and a finely filamentous lobular structure. Typically, it is associated with a multitude of vesicles. It is first clearly seen in mid- and late pachytene spermatocytes as an intermitochondrial dense material. During early spermiogenesis it is seen near the Golgi complex and frequently connected by material continuities through nuclear pore complexes with intranuclear particles. In living cells, the CB moves around the Golgi complex and has frequent contacts with it. The CB also moves perpendicularly to the nuclear envelope, and even through cytoplasmic bridges to the neighbour spermatids. One of the major components of the CB is a DEAD-box RNA helicase VASA that belongs to a class of proteins thought to act as RNA chaperones. It is a general marker of all germ cells and best characterized in Drosophila. The mouse VASA homologue was recently used as a marker of sperm formation from embryonic stem cells. It becomes generally accepted that the CB with its associated structures constitute a mechanism of post-transcriptional processing and storage of several mRNA species that are shared between neighbour cells and used for translation when the genome of the spermatids becomes inactive.
Parvinen
Martti
M
Department of Anatomy, University of Turku, FIN-20520 Turku, Finland. martti.parvinen@utu.fi
D000818:Animals; D002465:Cell Movement; D053487:DEAD-box RNA Helicases; D029721:Drosophila Proteins / Q000502:physiology; D004331:Drosophila melanogaster / Q000648:ultrastructure; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D009940:Organoids / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D020365:RNA Helicases / Q000502:physiology; D012332:RNA, Heterogeneous Nuclear / Q000096:biosynthesis; D051381:Rats; D013087:Spermatids / Q000648:ultrastructure; D013091:Spermatogenesis / Q000502:physiology*; D014750:Vincristine / Q000494:pharmacology
D029721:Drosophila Proteins; D011500:Protein Synthesis Inhibitors; D012332:RNA, Heterogeneous Nuclear; D014750:Vincristine; C487765:Ddx25 protein, mouse; C090864:Ddx4 protein, mouse; C088269:vas protein, Drosophila; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases