Ultrastructural characterization of RPA-containing domains in nuclei assembled in Xenopus egg extracts.
We describe novel structural domains in in vitro reconstituted Xenopus sperm nuclei, which we term RPA bodies; RPA is the only known marker of these structures. These bodies contain DNA and represent special chromatin domains as seen by transmission electron microscopy. We show that RPA bodies exhibit a similar ultrastructure in nuclei assembled in high-speed supernatant (HSS) of Xenopus egg extract and in nuclei assembled in HSS supplemented with low-speed supernatant (HSS + LSS nuclei). Moreover, RPA bodies are also formed when sperm chromatin containing double-stranded DNA breaks is incubated with HSS of egg extracts. RPA bodies appear to be compartmentalized. By immunoelectron microscopy we show that RPA is preferentially localized at the periphery of the bodies where DNA synthesis also occurs in HSS + LSS nuclei.
Eltsov
M
M
Department of Cell Biology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 2, Albertov 4, CZ-128 00, Czech Republic.
Grandi
P
P
Raska
I
I
D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D004268:DNA-Binding Proteins / Q000032:analysis*; D005260:Female; D008297:Male; D016253:Microscopy, Immunoelectron; D009865:Oocytes / Q000502:physiology*; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D051716:Replication Protein A; D013094:Spermatozoa / Q000648:ultrastructure; D014020:Tissue Extracts / Q000494:pharmacology; D014981:Xenopus
D004268:DNA-Binding Proteins; D051716:Replication Protein A; D014020:Tissue Extracts