Rna Intermediates of Viroid Replication 329
نویسنده
چکیده
Molecular hybridization by the Northern blot technique in combina t ion with 12SI-labeled PSTV (+) RNA and S2P-labeled PSTV cDNA as probes has been applied to d e t e c t v i r o i d s p e c i f i c s e q u e n c e s in h e a l t h y and v i r o i d ( P S T V ) i n f e c t e d t o m a t o plants . Conditions are described which allow d i f f e r e n t i a t i o n of (+) and (-) viroid sequences on the basis of the different thermostabilities of the corresponding hybrid molecu les . By this e x p e r i m e n t a l approach~ it is documented that no viroid-specific DNA sequences can be detected and that viroid r ep l i ca t ion proceeds via c o m p l e m e n t a r y RNA intermediates. Out of the seven (-) RNA species found~ six are appa ren t l y la rger than the circular viroid (+) RNA and one is about the same size as the linear (+) RNA molecule.
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Detection and analysis of hairpin II, an essential metastable structural element in viroid replication intermediates.
In (-)-stranded replication intermediates of the potato spindle tuber viroid (PSTVd) a thermodynamically metastable structure containing a specific hairpin structure (HP II) has been proposed to be essential for viroid replication. In the present work a method was devised allowing the direct detection of the HP II structure in vitro and in vivo using a biophysical approach. An RNA oligonucleoti...
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