Cloned Ribosomal RNA Genes from Chloroplasts of Euglena gracilis

Abstract

Fragments of Euglena chloroplast DNA generated by endonuclease R-Eco RI were separated by agarose-gel electrophoresis into 24 distinct bands. At least five fragments contain sequences complementary to chloroplast ribosomal RNA, Most of the Eco RI fragments have been cloned in a plasmid of Escherichia coli. Three of the cloned fragments were shown to contain chloroplast ribosomal RNA sequences by DNA-RNA hybridization.

Organization of the chloroplast ribosomal RNA genes of Euglena gracilis bacillaris

“…Plasmids were maintained in RH20I (F + thr leu thi lacY tonA supE hss) or its thr + leu + derivative RH202 (Adams et al, 1979). Cloning of E. gracilis bacillaris chloroplast DNA was carried out as described (Lomax et al, 1977;Helling and Lomax, 1978). All constructed plasmids (Table 1) were purified by transformation prior to use.…”

“…All constructed plasmids (Table 1) were purified by transformation prior to use. Plasmid and chloroplast DNA preparations have been described (Lomax et aL, 1977).…”

“…The Location and Arrangement of Ribosomal RNA Genes. Eco fragments B, F, M, O, R and S have been shown to hybridize with chloroplast rRNA (Lomax et al, 1977;Mielenz, Milner and Hershberger, 1977). Rawson et al, (1978) found that three sets of rRNA genes (rDNA) are clustered on the cloroplast genome of E. gracilis Z.…”

“…We have cloned a large part of the E. gracilis chloroplast DNA in plasmids of Escherichia coli (Lomax et al, 1977;this paper). The cloned DNA segments were generated by a variety of restriction endonucleases.…”

The Maintenance of Plasmid-containing Organisms in Populations of Escherichia coli

“…Plasmid-containing strains were obtained by transformation with purified plasmid DNA using the standard CaCl, procedure (Adams et al, 1979;El-Gewely & Helling, 1980). The ligation and cloning procedures have been described previously (Lomax et al, 1977). The plasmid composition was verified by the characteristic band patterns of the plasmid DNA observed after cleavage by site-specific endonucleases and separation by agarose gel Fig.…”