The Nuclear Envelope in Freeze-Etching

Kartenbeck, Jürgen; Zentgraf, Hanswalter; Scheer, Ulrich; Franke, Werner W.

doi:10.1007/978-3-662-10390-6

Cited by 15 publications

(10 citation statements)

References 124 publications

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“…Although corresponding calculations made from thin-sectioned material gave higher values, possibly as a result of slight shrinkage of nuclei during the dehydration stage of processing (cf. Kartenbeck et al, 1971) this difference is not statistically significant (P > 0.01). Thus, pore frequency data obtained by the three methods are comparable.…”

Section: Results a N D Discussionmentioning

confidence: 67%

A simple technique for the rapid preparation of freeze‐fracture replicas of plant nuclei

Severs

Jordan

1975

Journal of Microscopy

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Section: Results a N D Discussionmentioning

confidence: 67%

A simple technique for the rapid preparation of freeze‐fracture replicas of plant nuclei

Severs

Jordan

1975

Journal of Microscopy

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“…Increase of the oocyte diameter (--) and of the ooplastions tangential to nuclear envelope (cf. Franke and Scheer, 1970a,b;Kartenbeck et al, 1971). All three different electron microscopic preparative methods gave nearly identical data (for a detailed methodical discussion see Kartenbeck et al, 1971), thus allowing the conclusion that the quantitative structural data of the nuclear envelope are unaffected by methodical artifacts.…”

Section: Structural Data Of the Nuclear Envelope During Oogenesismentioning

confidence: 96%

Nuclear pore flow rate of ribosomal RNA and chain growth rate of its precursor during oogenesis of Xenopus laevis

Scheer

1973

Developmental Biology

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The numb er of ribosomal RNA mol ecules which are transferred through an average nuclear pore complex per minute into the cytoplasm (nuclear pore flow rate, NPFR) during oocyte growth of Xenopus laevis is estimated. The NPFR calculations are based on determinations of the increase of cytoplasm ic rRNA conten t during defined time intervals and of the total number of pore complexes in the respective oogenesis stages. In the mid-la mpbrush stage (500:"700 I'm oocyte diameter) the NPFR is maximal with 2.62 rRNA molecules/ pore/ minute. Then it decreases to zero at the end of oogenesis. The nucleocytoplasmic RNA f10w rates determined are compared with corresponding va lues of other cell types. The molecular weight of the rRNA precursor transcribed in t he extrachromosomal nucleoli of Xenopus la mpbrush stage oocytes is determined by acrylamide ge l electrophoresis to be 2.5 x 10· daltons. From the temporal increase of cytoplasmic rRNA (3.8 I'g per oocyte in 38 days) and the known number of simultaneously grow ing precursor molecules in the nucleus the chain growth rate of the 40 S precursor RNA is estimated to be 34 nucleotides per second.

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“…Shrinkage during fixation would cause a systematic error in these numbers. Freeze etching is the most quantitative method to measure density (Maul, 1977), and Kartenbeck et al (1971) compared the values they obtained in rat hepatocytes using both transmission EM and freeze etching. They found that the density of pores in thin section is larger than the density of pore in freeze etch.…”

Section: Density Of Pores In the Nuclear Envelopementioning

confidence: 99%

Ion channels in murine nuclei during early development and in fully differentiated adult cells

1991

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The nuclear envelope functions as a selective barrier between nucleus and cytoplasm. During cycles of cell division the nuclear envelope repeatedly disassembles and re-associates. Presumably, each cycle re-establishes the functional and structural integrity of the nuclear envelope. After repeated rounds of cell division, as occurs during differentiation, the selectivity and configuration of the envelope may change. We compare the ionic conductance and the nuclear pore density in four types of murine nuclei: germinal vesicles in oocytes, pronuclei in zygotes, nuclei from two-cell blastomeres, and somatic cell nuclei from the liver. A large-conductance ion channel is present in all nuclear envelopes. Liver cell nuclei have a greater number of these channels than those from earlier developmental stages, and they also have a higher density of nuclear pores. In this article we hypothesize an association between the ion channels and the nuclear pores.

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The Nuclear Envelope in Freeze-Etching

Cited by 15 publications

References 124 publications

A simple technique for the rapid preparation of freeze‐fracture replicas of plant nuclei

A simple technique for the rapid preparation of freeze‐fracture replicas of plant nuclei

Nuclear pore flow rate of ribosomal RNA and chain growth rate of its precursor during oogenesis of Xenopus laevis

Ion channels in murine nuclei during early development and in fully differentiated adult cells

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