Objective    To study whether the oncoprotein

Bcr-Abl

can be degraded by ubiquitin-proteasome target system and its role in induction of apoptosis of leukemia K562 cells.     Methods    Chimeric ubiquitin ligase

β-TrCP

was transported to target K562 cells by Ad5β-TrCP-OD-HA recombinant adenoviruses carrying N-terminal oligomerizaton domain (OD) of Bcr-Abl that can specifically bind to its N-terminal OD through infection. Meanwhile

recombinant adenoviruses with mutational β-TrCP gene（Ad5△F-TrCP-OD-HA）and green fluorescent protein gene（Ad5GFP）were used as controls

respectively. After infection

expression of Bcr-Abl was detected by Western blotting. Cell morphology was observed under inverted

light and electron microscopes

respectively.     Results    The leukemia K562 cell clones with exogenous recombinant β-TrCP-OD-HA or △F-TrCP-OD-HA gene were established. After infection with recombinant viruses

the expression level of Bcr-Abl was lower in Ad5β-TrCP-OD-HA than in Ad5GFP and controls (P0.05). Inverted microscopy demonstrated small-sized cells in irregular shape

light microscopy showed small-sized cells

vacuolation in cytoplasm

cleavage of nuclei

and apoptotic bodies

and electron microscopy revealed typical ultrastructure of apoptotic cells

after treatment with Ad5β-TrCP-OD-HA.     Conclusion    Recombinant adenoviruses-induced β-TrCP-OD-HA can reduce Bcr-Abl in leukemia K562 cells and induce their apoptosis.