The Nanovirus-Encoded Clink Protein Affects Plant Cell Cycle Regulation through Interaction with the Retinoblastoma-Related Protein

• DOI: 10.1128/jvi.02103-06
• Publication Date: 2007-02-03T02:42:26Z
• Authors: Sébastien Lageix; Olivier Catrice; Jean-Marc Deragon; Bruno Gronenborn; Thierry Pélissier; Bertha Cecilia Ra...
• Keywords: Retinoblastoma protein; Transcription; Retinoblastoma

Nanoviruses, multicomponent single-stranded DNA plant viruses, encode a unique cell cycle link protein, Clink, that interacts with retinoblastoma-related proteins (RBR). We have established transgenic Arabidopsis thaliana lines conditionally express Clink or variant deficient in RBR binding. By controlled induction of expression, we demonstrated the capacity protein to alter function vivo. showed transcription both S-phase-specific and G2/M-phase-specific genes was up-regulated depending on RBR-binding proficiency Clink. Concomitantly, ploidy levels increased substantial fraction leaf nuclei. Also, epidermis cells plants producing were smaller more numerous, indicating additional divisions this tissue. Furthermore, cytogenetic analyses following expression mature leaves revealed presence metaphasic anaphasic nuclei, clear evidence Clink-mediated inactivation is sufficient induce quiescent reenter progression and, for at least them, pass through mitosis. Expression had no effect transcribed by RNA polymerases I III, suggesting that, contrast its mammalian homologue, A. not involved repression polymerase III transcription. The results these vivo firmly establish as member diverse class multifunctional modulator encoded small viruses.