TY  - JOUR
A1  - Trendelenburg, Michael F.
A1  - Scheer, Ulrich
A1  - Franke, W. W.
T1  - Structural organization of the transcription of ribosomal DNA in oocytes of the house cricket
N2  - No abstract available
Y1  - 1973
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33113
ER  - 
TY  - JOUR
A1  - Trendelenburg, Michael F.
A1  - Scheer, Ulrich
A1  - Zentgraf, Hanswalter
A1  - Franke, Werner W.
T1  - Heterogeneity of spacer lengths in circles of amplified ribosomal DNA of two insect species, Dytiscus marginalis and Acheta domesticus
N2  - No abstract available
Y1  - 1976
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33055
ER  - 
TY  - CHAP
A1  - Trendelenburg, Michael F.
A1  - Spring, Herbert
A1  - Scheer, Ulrich
A1  - Franke, Werner W.
T1  - Morphology of nucleolar cistrons in a plant cell, Acetabularia mediterranea
N2  - The structural organization of transcriptionally active DNA that contains cistrons for precursor molecules of ribosomal RNA is described in positively stained spread preparations from nuclei and nucleoli isolated from the green alga, Acetabularia mediterranea Lmx. These nuclei contain large aggregates of nucleolar subunits in which fibril-covered regions, the putative active cistrons for precursors of ribosomal RNA, alternate with fibril-free intercepts, the "spacers". The length distribution of the different intercepts of this DNA is given, and the pattern is compared with those shown in animal cell systems. The data are discussed in relation to problems of transcription and of amplification of ribosomal RNA genes.
KW  - ribosomal RNA genes; electron microscopy; spread preparations
Y1  - 1974
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32213
ER  - 
TY  - JOUR
A1  - Zentgraf, Hanswalter
A1  - Trendelenburg, Michael F.
A1  - Spring, Herbert
A1  - Scheer, Ulrich
A1  - Franke, Werner W.
A1  - Müller, Ulrike
A1  - Drury, Kenneth C.
A1  - Rungger, Duri
T1  - Mitochondrial DNA arranged into chromatin-like structures after injection into amphibian oocyte nuclei
N2  - Purified mitochondrial DNA (mitDNA) from ovaries ofXenopus lae vis was injected into the nuclei (germinal vesicles) of large viteUogenic oocytes of the same organism and examined by electron microscopy ofthe spread nuclear contents. Normally located nuclei of untreated oocytes as weil as peripherally translocated nuclei of centrifuged oocytes were used. In addition, oocyte nuclei isolated and incubated under liquid paraffin oil were injected with DNA. The integrity oftranscriptional structures of endogenous chromosomal (Iampbrush chromosomes) and extrachromosomal (nucleoli) genes of the injected nuclei was demonstrated. Microinjected mitDN A was identified as circles of chromatin exhibiting polynucleosome-like organization and a me an contour length of 2.6 J.Lm, corresponding to a compaction ratio of the mitDN A of about 2 : I. This DNA packing ratio is similar to that observed after preparation of various kinds of native chromatin in low salt buffers. The chromatin circles formed from injected mitDNA only very rarely exhibited lateral fibrils suggestive of transcriptional activity. These results suggest that purified mitDNA can be transformed to normally structured chromatin when exposed to oocyte nuclear contents but is rarely , if at all , transcribed in this form and in this environment.
Y1  - 1979
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33174
ER  -