A ribonuclease activity is activated by heparin or by digestion with proteinase K in mitochondrial extracts of Leishmania tarentolae

• Published in: The Journal of biological chemistry Vol. 267; no. 10; pp. 6782 - 6788
• Main Authors: Simpson, A M, Bakalara, N, Simpson, L
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 05.04.1992
• Subjects: Animals; Base Sequence; Cytochrome b Group - genetics; Electrophoresis, Polyacrylamide Gel; Endopeptidase K; Enzyme Activation; Heparin - pharmacology; Leishmania - enzymology; Leishmania tarentolae; Mitochondria - enzymology; Molecular Sequence Data; Nucleic Acid Conformation; Ribonucleases - metabolism; RNA Processing, Post-Transcriptional; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Ribosomal - genetics; RNA, Ribosomal - metabolism; Serine Endopeptidases - metabolism; Transcription, Genetic
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)50494-X

A ribonuclease activity in a 100,000 x g supernatant of a Triton lysate of a mitochondrial-kinetoplast fraction from Leishmania tarentolae is activated by incubation with heparin or by predigestion of the lysate with proteinase k or pronase. In vitro-transcribed pre-edited cytochrome b mRNA is cleaved at several sites. With time, complete degradation of the RNA occurs. All cleavages occurred within putative single-stranded regions of the RNA. No cleavage was observed with 9 S rRNA. The presence of a nonspecific nucleotide or nucleoside slows the rate of cleavage. The cleavage activity is inhibited by sodium dodecyl sulfate or phenol/chloroform extraction, is retained by a 10-kDa cutoff filter, and passes through a 30-kDa filter. Micrococcal nuclease inhibits the proteinase-induced activity but not the heparin-induced activity.