Electron microscopic localization of the chloroplast DNA replicative origins in Chlamydomonas reinhardii.
AUTOR(ES)
Waddell, J
RESUMO
Chloroplast DNA, isolated from a synchronized culture of Chlamydomonas reinhardii, was digested with restriction endonucleases and examined in the electron microscope. Restriction fragments containing displacement loops (D-loop) were photographed and measured to determine the position of replicated sequences in relation to the restriction enzyme sites. D-loops were located at two positions on the physical map of chloroplast DNA. One replication origin was mapped at about 10 kb upstream of the 5' end of a 16s rRNA gene. The second origin was spaced 6. 5kb apart from the first origin and was about 16.5 kb upstream of the same 16s rRNA. Initiations at those two sites were not always synchronized. Replication initiated with the formation of a D-loop resulting from the synthesis of one daughter strand. After a short initial lag phase, corresponding to the synthesis of 350 +/- 130 bp of one daughter strand, DNA synthesis then proceeded in both directions. Both D-loop regions were preferred binding sites of undetermined protein complexes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=318794Documentos Relacionados
- Sequence organization of repetitive elements in the flanking regions of the chloroplast ribosomal unit of Chlamydomonas reinhardii.
- Sequence of the chloroplast 16S rRNA gene and its surrounding regions of Chlamydomonas reinhardii.
- Localization and sequence analysis of chloroplast DNA sequences of Chlamydomonas reinhardii that promote autonomous replication in yeast
- Localization of replication origins in pea chloroplast DNA.
- Cloning and delimiting one chloroplast DNA replicative origin of Chlamydomonas.
