The Structural And Founctional Study Of Promylocyte Leukemia Protein B1-box

Pro Myelocytic Leukemia(PML)protein can polymerize into a nuclear assembly of0.1-2 μm in diameter called/named PML nuclear body.The mature PML nuclear body could mediate numerous cellular biological processes,including genomic stability regulation,transcriptional regulation,protein post-translational modification,cell cycle regulation,immune regulation,antiviral response,cell senescence and apoptosis,etc.However,the mechanism of PML nuclear body biogenesis remain elusive.As the key component,PML has drawn many researchers’ attention from all over the world.Studies show that due to DNA alternative splicing at the C terminal of PML,it can give birth to isoforms I-VII,which are all participate in PML NB assembly.And all the isoforms harbor a concerved RBCC domain,RING、B1-box、B2-box、Coiled coil domain,which is the foundation of PML NB assembly.Thanks to the successfully purified PML RBCC fragment,we observed a previously unrecognized sequential oligomerization mechanism via PML monomer,dimer,tetramer and N-mers through the gel filtration and ultracentrifugation analysis.Consistently,PML B1-box crystal structure(2.0 (?))and SAXS characterization reveal an unprecedented networking by W157-,F158-and SD1-interfaces.Structure-based perturbations on these B1 interfaces not only impair oligomerization in vitro,but also abolish PML SU(44)Oylation and nuclear body formation in celluo.The translocation of chromosomes 15 and 17 generateing pml/rarα fusion gene is the basis of acute promyelocytic leukemia(APL)pathogenesis.More importantly,targeting the B1-B1 interaction by F158 E significantly alters PML/RARα-driven transcription and it also precludes leukemogenesis which is demonstrated by transgenic mice technology.Besides,single cell analysis of transgenic mice bone morrow cells identify new genes never been reported before.Therefore,these results not only define an unprecedented B1-box oligomerization in PML,but also highlight oligomerization as an important factor in carcinogenesis.Moreover,B1-box mediated polymerization can also affect the reaction of PML and PML/RARα to arsenic,which also provides new ideas for the new drugs discovery.