The bridge-partitioning complex of germ-cell intercellular bridges in the testis of the golden hamster.
The bridge-partitioning complex present in pre-existing intercellular bridges of dividing spermatogonia in the juvenile golden hamster testis was studied by electron microscopy. There is a close temporal adjustment in the appearance of this structure to those stages of mitosis during which the cells are without a nuclear membrane, i.e., the bridge-partitioning complex is formed at the transition between prophase and prometaphase and gradually disappears during telophase. In addition, in a certain form of degenerative dividing germ cells, which completely lack a bridge-partitioning complex in pre-existing intercellular bridges, condensed chromatin not surrounded by a nuclear membrane occasionally projects through these open bridges and thus may well change over to a neighboring cell of the same clone. These results strongly indicate an essential barrier function of the bridge-partitioning complex. It temporarily prevents intraclonal exchange of nuclear material during those stages of mitosis where a nuclear membrane is lacking and, thus, maintains genetic integrity of male germ cells during synchronous divisions.
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Anatomisches Institut der Universität Bonn, Germany.
D000818:Animals; D006224:Cricetinae; D008297:Male; D008647:Mesocricetus; D008938:Mitosis; D013093:Spermatogonia / Q000648:ultrastructure*; D013737:Testis / Q000166:cytology*