Migration of newly synthesized RNA during mitosis I. Embryonic cells of the loach (Misgurnus fossilis L.)

Neyfakh, Alexander A.; Kostomarova, A A

doi:10.1016/0014-4827(71)90011-5

Cited by 16 publications

(2 citation statements)

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“…However, in short-term labeling experiments with RNA precursors, most of the incorporation of isotope occurs in nuclear heterodisperse (chromosomal) RNA which turns over rapidly within the nucleus (Scherrer et al, 1966). Several experiments, however, make it appear that such rapidly labeled HnRNA is shed from the chromosomes during prophase, resides in the cytoplasm during mitosis, and is returned to the nucleus after mitosis (Rao and Prescott, 1967;Neyfakh and Kostomarova, 1971 ; In our laboratory we have observed radioautographically that, in cells in winch ribosomal RNA synthesis has been suppressed, rapidly labeled RNA leaves the chromosomes and appears in the cytoplasm late in prophase (unpuNished). This rapidly labeling RNA obscures the fate of the ribosomaI precursor RNA in radioautographs.…”

Section: Discussionmentioning

confidence: 80%

“…Radioautographic investigations generally have not demonstrated the existence of RNA on metaphase chromosomes In fact, when cells are labeled before mitosis with radioactive RNA precursors and then radioautographed, the mitotic chromosomes appear to be unlabeled (at least relative to other structures) (Freedman et al, 1967;Neyfakh and Kostomarova, 1971;Neyfakh et aI., 1971). However, in short-term labeling experiments with RNA precursors, most of the incorporation of isotope occurs in nuclear heterodisperse (chromosomal) RNA which turns over rapidly within the nucleus (Scherrer et al, 1966).…”

Section: Discussionmentioning

confidence: 99%

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Repopulation of the Postmitotic Nucleolus by Preformed Rna

Phillips

1972

The Journal of Cell Biology

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ABSTRA_CTThis study is concerned with the fate of the nucleolar contents, particuIartv nucleolar RNA, during m~tosis Mitotic cells harvested from monolayer cultures of Chinese hamster embryonal cells, XB6 (human) cells, or L929 (mouse) cells were allowed to proceed into mterphase in the presence or absence (control) of 0.04-0 08 /~g/ml of actinomycin D, a concentration which preferentially inhibits nucleolar (nbosomal) RNA synthesis 3 hr after mitosis, control cells had large, irregularly shaped nucleoli which stained intensely for RNA with azure B and for protein with fast green. In cells which had returned to interphase in the presence of actinomycin D, nucleoli were segregated into two components easily resolvable in the light microscope, and one of these components stained intensely for RNA with azure B. Both nucleolar components stained for protein with fast green In parallel experiments, cultures were incubated with 0.04-0 08 #g/ml actinomycm D for 3 hr before harvesting of mitotic ceils, then mitotic cells were washed and allowed to return to interphase in the absence of actinomycin D. 3 hr after mitosis, nuclei of such ceils were devoid of large RNA-containing structures, though small, refractile nucleolus-like bodies were observed by phase-contrast microscopy or in material stained for total protein. These experiments indicate that nucleolar RNA made several hours before mitosis persists in the mitotic cell and repopulates nucleoli when they reform after mitosis

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Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%