RNA-Hydrolyzing Antibodies from Peripheral Blood of Patients with Lupus Erythematosus

A. V. Vlasov,¹ O. A. Andrievskaya,¹ T. G. Kanyshkova,¹ A. G. Baranovsky,¹ V. A. Naumov,² A. A. Breusov,² R. Giege,³ V. N. Buneva,¹ and G. A. Nevinsky^1,4

¹Novosibirsk Institute of Bioorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, pr. Lavrent'eva 8, Novosibirsk, 630090 Russia; fax: (3832) 35-16-65; E-mail: nev@modul.bioch.nsk.su

²District Military Hospital, ul. Voinskaya 24, Novosibirsk, 630017 Russia.

³Institut de Biologie Moleculaire et Cellulaire du CNRS, 15, rue Rene Descartes, Strasbourg 67000, France.

⁴To whom correspondence should be addressed.

Submitted March 22, 1996; revision submitted January 13, 1997.

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Experiments with hydrolysis of substrates with known spatial structures (such as yeast tRNA^Phe, as well as normal and mutant tRNA^Lys from human mitochondria produced by transcription of the appropriate DNA species, that is, RNA genes) were performed to study the ribonuclease activity of antibodies isolated from blood sera of patients with systemic lupus erythematosus (SLE). The antibody preparations contained two types of ribonuclease activities: the first corresponded to the specificity of ribonuclease A and was found during hydrolysis at low salt concentrations, whereas the second was stimulated by Mg²⁺ and displayed a unique specificity toward double-stranded regions of the substrate. The possible use of the antibody preparations as tools for structural studies of conformational differences between RNA molecules was examined. In experiments with unmodified and mutant tRNA^Lys species differing in one base found in the T-loop, we found that hydrolysis with SLE antibodies can detect small local structural changes in RNA under physiological conditions.

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KEY WORDS: catalytic antibodies, systemic lupus erythematosus, ribonucleases, tRNA.

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