THE p21WAF1 CYCLIN-KINASE INHIBITOR IN VIVO
INTERACTS WITH E1A ADENOVIRAL AD2 AND AD12 ONCOPROTEINS
O. V. Timofeev, V. A. Pospelov 1
Institute of Cytology RAS, St. Petersburg, Russia;
1 e-mail: vap@mail.cytspb.rssi.ru
The capability of adenoviral oncoproteins E1A Ad2 and Ad12 to form complexes in vivo with cyclin-kinase inhibitor
p21Waf1 has been analysed. The published data confirming direct interaction between E1A and p21Waf1
are insufficient. In the present work, a yeast two-hybrid SRS system was used to investigate the binding of different fragments of E1A Ad2
and Ad12 polypeptides with p21Waf1. We have shown that the full length product of 12S mRNA E1A Ad2 interacts weekly
with p21Waf1, whereas the protein corresponding to 13S mRNA E1A Ad12 does not bind to cyclin-kinase inhibitor protein.
Moreover, fragments 1-80 (Ad2), 1-29 (Ad12), 1-79 (Ad12), and 105-194 (Ad12) were able to interact with p21Waf1 to some
extent. The difference between interacting regions of adenoviral proteins E1A Ad2/5 and Ad12 gives a new information about the
mechanism of p21Waf1 functional inactivation and different transforming activity of Ad2/5 and Ad12.
Key words: G1/S block, E1A, p21Waf1, cyclin-kinase complexes
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