title: Sequence organization of a cloned tDNA met fragment from Xenopus laevis.
abstract: 3.18 kb fragments of X. laevis DNA coding for tRNA 1 met have been inserted into a lambda vector via Hind III termini and cloned in E. coli. The organization of one cloned fragment has been analyzed by restriction endonuclease digestion and RNA-DNA hybridization. From the distribution of sites for three enzymes, this fragment appears to be typical of the majority of X. laevis tandem tDNA 1 met repeat units. Evidence is presented to suggest that it contains two genes coding for tRNA 1 met and at least one gene coding for a second as yet unidentified 4S RNA species. The two tRNA 1 met genes are located on the same DNA strand 0.96 and 1.38 kb from one end of the repeat unit. A detailed restriction map for 19 enzymes reveals that the spacers between these genes are not identical, and it provides no indication of short repetitive sequence elements within the spacers.
mesh_terms: D000818:Animals; D003090:Coliphages; D004247:DNA / Q000235:genetics; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant; D005796:Genes; D008040:Genetic Linkage; D008715:Methionine; D012343:RNA, Transfer / Q000235:genetics*; D014981:Xenopus / Q000235:genetics*
chemical_list: D004274:DNA, Recombinant; D004247:DNA; D012343:RNA, Transfer; D008715:Methionine; D004262:DNA Restriction Enzymes