Nucleic Acids Research, 1980, Vol. 8, No. 13 2947-2966
© 1980
MOLECULAR BIOLOGY |
Transcriptional mapping of the ribosomal RNA region of mouse L-cell mitochondrial DNA
Department of Pathology, Stanford University School of Medicine Stanford, CA 94305, USA
Received April 30, 1980. The map positions in mouse mitochondrial DNA of the two ribosomal RNA genes and adjacent genes coding several small transcripts have been determined precisely by application of a procedure in which DNA-RNA hybrids have been subjected to digestion by Sl nuclease under conditions of varying severity. Digestion of the DNA-RNA hybrids with Sl nuclease yielded a series of species which were shown to contain ribcaomal RNA molecules together with adjacent transcripts hybridized conjointly to a continuous segment of mitochondrial DNA. There is one small transcript about 60 bases long whose gene adjoins the sequences coding the 5'-end of the small ribosomal RNA (950 bases) and which lies approximately 200 nucleotides from the D-loop origin of heavy strand mitochondrial DNA synthesis. An 80-base transcript lies between the small and large ribosomal RNA genes, and genes for two further short transcripts (each about 80 bases in length) abut the sequences coding the 3'-end of the large ribosomal RNA $$$500 bases). The ability to isolate a discrete DNA-RNA hybrid species approximately 2700 base pairs in length containing all these transcripts suggests that there can be few nucleotides in this region of mouse mitochondrial DNA which are not represented as stable RNA species.