Characterization of two murine (2'-5')(A)n-dependent endonucleases of different molecular mass.
RNase L is considered as the major if not unique target of (2'-5')(A)n and therefore as an important intracellular mediator of interferon action. It behaves as an 185-kDa species in various cell extracts when analyzed by gel filtration. SDS/PAGE analysis of the polypeptides covalently labelled with a (2'-5')(A)4-3'-[32P]pCp probe reveals a single 80-kDa species, thus attesting a multimeric form of the 185-kDa protein. At variance with such data, mouse spleen extracts reveal an additional 40-kDa polypeptide with (2'-5')(A)n-dependent ribonucleolytic activity. This seemingly new form of RNase L migrates as a 40-kDa polypeptide when analyzed under native or denaturing conditions. It bears some structural similarity with the larger-molecular-mass RNase L as revealed by partial proteolysis. It is probably not generated through proteolytic degradation of the 185-kDa RNase L during extract preparation, although its physiological significance is unknown. Indeed various protease inhibitors do not significantly alter the ratio of 40-kDa and 185-kDa (2'-5')(A)n-dependent ribonucleases; moreover, the (2'-5')(A)n-binding capacity of the 40-kDa polypeptide is more stable than that of the 185-kDa one.
Bisbal
C
C
Laboratoire de Biochimie des Proteines, URA CNRS 199, Université des Sciences et Techniques, Languedoc, Montpellier, France.
Salehzada
T
T
Lebleu
B
B
Bayard
B
B
D000227:Adenine Nucleotides / Q000096:biosynthesis; D000345:Affinity Labels; D000818:Animals; D002850:Chromatography, Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D004722:Endoribonucleases / Q000032:analysis* / Q000096:biosynthesis; D006367:HeLa Cells; D006358:Hot Temperature; D007526:Isoelectric Point; D007942:Leukemia, Experimental; D008297:Male; D051379:Mice; D008970:Molecular Weight; D009843:Oligoribonucleotides / Q000096:biosynthesis; D010449:Peptide Mapping; D013154:Spleen / Q000032:analysis; D013329:Structure-Activity Relationship
D000227:Adenine Nucleotides; D000345:Affinity Labels; D009843:Oligoribonucleotides; C023505:2',5'-oligoadenylate; C033547:2'-5'-oligo(A)-dependent endonuclease; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease