"Prophasing" as a possible cause of chromosome translocation in virus-fused cells.

Abstract

Fusion of a metaphase cell with an interphase cell by means of Sendai virus leads the latter nucleus to undergo a unique transformation, being termed as “chromosome pulverization”1, “premature chromosome condensation”3, or “pro-phasing”3. This phenomenon has been ascribed to the mitotic asynchrony between the interphase and metaphase nuclei of the progeny cells2–5. The morphological changes of the interphase nucleus simulated the normal sequence of events which occurs in a G2-mitosis transition5 (for example, chromatin condensation, disruption of nuclear membrane, formation of kinetochore, and orientation of spindle tubules). Hence, the term “prophasing” is inferred most relevant to this particular phenomenon. The chromatin subjected to prophasing is not necessarily disrupted5, but could survive as morphologically intact chromosomes6. During an autoradiographic study on the fate of the “prophasing” chromatin in virus-fused cells, I have observed incidental chromosome translocations in the progeny, which failed to occur if there was no “prophasing” beforehand.