Newborn mouse DNA was digested with a restriction endonuclease EcoRI and concentrated with respect to ribosomal RNA sequences by an RPC-5 column.
DNA fragments of 14-17 kilobases in length, most probably containing promoter region of the ribosomal RNA gene, were used for cloning with λgt
WES•λB as a vector using an
in vitro packaging technique. Several clones containing 18S rRNA sequences were obtained. One of the clones which was transferred to a plasmid pBR322 (designated as pMrEL-1) was 14 kilobases in length, having only a part of 18S rRNA sequence. These results strongly suggest that this fragment carries a promoter region of the ribosomal RNA gene.
View full abstract