Investigations on chromatin condensation of hen erythrocyte nuclei in vitro

Coutelle, Ch.; Belkner, J; Prehn, Siegfried; Rosenthal, Stephen M.; David, Heinz; Dreher, Ralf-Michael

doi:10.1016/0014-4827(74)90612-0

Cited by 9 publications

(4 citation statements)

References 32 publications

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“…The final preparation contained 218 J)-g of RNA as could be determined colorimetrically, in the presence of only minor quantities of DNA retained, and from the degradation by pancreatic ribonuclease. Having controlled the recoveries of labelled RNA and DNA added to aliquots processed in parallel and that of total DNA after each of the individual preparative steps we have found that the minimal RNA content per hen erythrocyte nucleus, and roughly also per total erythrocyte, is from 0.02 to 0.04 pg, corresponding to about 1-2 % of the DNA present (for chromatin preparations see also [3,40]; published figures for DNA contents per hen or chicken erythrocyte nucleus vary from 1.7 to 3.5 pg [5,17,63,67]). …”

Section: Estimation Of Minimal Rna Content Of Mature Hen Erythrocytesmentioning

confidence: 92%

“…The literature contains controversial data as to the amount of RNA present in the nucleus of the avian erythrocyte (ranging from zero to 0,12 pg, cf [17,19,41,67]). …”

Section: Estimation Of Minimal Rna Content Of Mature Hen Erythrocytesmentioning

confidence: 99%

“…The formation of the red blood cell, in particular in animals with nucleated erythrocytes , has become of special importance in studie s of the programmed switch-off sequence of the transcription of most, and finally perhaps of all, genes. It has been shown that during erythropoiesis the nuclear content and the nuclear envelope is greatly reduced , the chromatin condenses and contains an additional special histone , the nucleolus disappears, concomitant with the cessation of ribosome formation , the number of transcribed genes decreases , leaving the transcription of one class of genes in the late erythroblast, namely the codons of the precursor molecules of globin mRNAs [4,17,25,27,29,41,48,54,57,59]. Fully mature erythrocytes are believed to be cells completely inactive in RNA formation [15,16,31,48,49,54] and without significant amounts left of the common cytoplasmic structures such as ribosomes and endomembranes [27 , 30, 67].…”

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Characterization and localization of the RNA synthesized in mature avian erythrocytes

Zentgraf

Scheer

Franke

1975

Experimental Cell Research

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Experimental Cell Research 96 (1975) RNA present and synthesized in mature hen erythrocytes in vivo and in vitro has been studied with electron microscopic , autoradiographic , and biochemical methods. The average hen erythrocyte contains a minimum of 0.02-0.04 pg RN A which is predominantly, if not exclusively, located in the nucleus. The incorporation of[3HJuridine into this RNA is very low but is clearly demonstrable in vivo and in vitro using different incubation media. The specific efficiencies of the incorporation assays are compared. The incorporated radioactivity is contained in RN A as shown by its selective sensitivity to hydrolysis in mild alkali and with ribonuclease a nd is not hybridized to DNA as shown by Cs.SO" gradient centrifugation of total hen erythrocyte nucleic acids. LiCI precipitation as well as gel electrophoresis on agarose under denaturing and non-denaturing conditions has revealed that this labelled RNA is of high-molecular weight a nd covers a broad range from ca 0.25 to 5.0 million D, with gel-electrophoretically detectable peaks at positions corresponding to 1.8, 1.0 and 0.5 million D. The pattern obtained is virtually identical after the different incorporation condi tion s and was also sim il ar to that obtained in reticulocyte cells of animals made anaemic with phenylhydrazine. The incorporation is inhibited by actinomycin D with a sensitivity characteristic for mRN A formation a nd is also reduced in the presence of a-amanitin. The labelled RNA remains within th e confinements of the nucleus and does not seem to be transported into the cytoplasm. It appears to be preferentially enriched in the interchromatinic channels . It is concluded that mature hen erythrocytes are capable of transcribing a small part of their genome into pre-mRNA at a very reduced level but that this RNA is not only excluded from functioning in tra nslation but also from nucleocytoplasmic transport. The findings are discussed in relation to the controversial literatu re in this field, a nd possible functions of thi s RNA are hypothesized.Various forms of cell differentiation are characterized by a progressive cessation of the sy nthesis of most, if not all, classes of RNA. In some late stages of such differentiation processes one even notes a general breakdown of RNA-containing structures and the mature cell is almost emptied of RNA . The formation of the red blood cell, in particular in animals with nucleated erythrocytes , has become of special importance in studie s of the programmed switch-off sequence of the transcription of most, and finally perhaps of all, genes. It has been shown that during erythropoiesis the nuclear content and the nuclear envelope is greatly reduced , the chromatin condenses and contains an additional special histone , the nucleolus disappears, concomitant with the cessation of ribosome formation , the number of transcribed genes decreases , leaving the transcription of one class of genes in the Exprl Cell Res 96 (1975)

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Section: Estimation Of Minimal Rna Content Of Mature Hen Erythrocytesmentioning

confidence: 92%

“…The literature contains controversial data as to the amount of RNA present in the nucleus of the avian erythrocyte (ranging from zero to 0,12 pg, cf [17,19,41,67]). …”

Section: Estimation Of Minimal Rna Content Of Mature Hen Erythrocytesmentioning

confidence: 99%

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confidence: 99%

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Characterization and localization of the RNA synthesized in mature avian erythrocytes

Zentgraf

Scheer

Franke

1975

Experimental Cell Research

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“…For mature chicken erythrocytes, swelling starts in "physiological" phosphate buffer above pH 7.4 (36), and the nuclear diameter increases dramatically (Fig. 3, top left panel) in low salt media such as LS (1 mM Tris, 0.1 mM EDTA, pH 8.5), a buffer used to spread nuclear chromatin for electron microscopy (37).…”

Section: Isolation Of Chicken Granulocytes and Immunolocalization Ofmentioning

confidence: 99%

Chromatin Structure in Granulocytes

Grigoryev

Woodcock

1998

Journal of Biological Chemistry

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To study the mechanism of heterochromatin formation in vertebrate cells, we isolated nuclei from chicken polymorphonuclear granulocytes and examined the chromatin organization. We found granulocyte chromatin to remain insoluble after nuclease digestion and to be resistant to swelling in low salt/high pH media. Both insolubility and resistance to swelling were lost after washing with 0.3 M NaCl, a procedure that released two abundant tissue-specific proteins from granulocyte nuclei. One of them (42 kDa) is identified as MENT, a protein previously shown to be associated with repressed chromatin from mature chicken erythrocytes. We show that MENT is immunolocalized in granulocyte heterochromatin, where it is one of the most abundant chromatin proteins (ϳ2 molecules/200 base pairs of DNA). MENT is the first nuclear protein structurally related to the serine protease inhibitor family. The other abundant protein is similar to or identical with mim-1, a myeloid-specific protein that is known to be stored in cell granules and to associate with isolated nuclei. MENT (but not mim-1) binds chromatin and free DNA, and, at its physiological protein/DNA ratio, enhances compaction and the reversible Mg 2؉ -dependent self-association of nucleosome arrays. MENT appears to promote the formation of heterochromatin by acting as a "glue" within and between chains of nucleosomes.

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