Search bioRxivSearch

Biology subjects

Wu, S. K.

Publications and source records attributed to Wu, S. K..

2 recordsLinked to original sources

The Senescence-Associated-Secretory-Phenotype induced by centrosome amplification constitutes a pathway that activates Hypoxia-Inducible-Factor-α.

The Senescence-Associated-Secretory Phenotype (SASP) promote paracrine invasion however may also suppress tumour growth, thus generating complex phenotypic outcomes. Although centrosome amplification can induce proliferation arrest, the subsequent fate of cells with centrosome amplification remains elusive. Here, we report that centrosome amplification induces a variant SASP, constituting a pathway activating paracrine invasion. The centrosome amplification SASP is non-canonical as it lacks detectable DNA damage or prominent NF-{kappa}B activation. Instead, involving Rac activation and reactive oxygen species production. Consequently, inducing hypoxia-inducible factor 1 and associated genes, which includes pro-migratory factors such as ANGPTL4. Since senescent cells also have poor fitness, it is tempting to speculate that centrosome amplification induced SASP is one explanation for why extra centrosomes promote malignancy in some experimental models but are neutral or inhibitory in others.

cell biology

RNA matchmaking remodels lncRNA structure and promotes PRC2 activity

Human Polycomb Repressive Complex 2 (PRC2) catalysis of histone H3 lysine 27 methylation at certain loci depends on long noncoding RNAs (lncRNAs). Yet, in apparent contradiction, RNA is a potent catalytic inhibitor of PRC2. Here we show that intermolecular RNA-RNA interactions between the lncRNA HOTAIR and its target genes can relieve RNA inhibition of PRC2. RNA matchmaking is promoted by heterogenous nuclear ribonucleoprotein (hnRNP) B1, which uses multiple protein domains to bind regions of HOTAIR via multi-valent protein-RNA interactions. Chemical probing demonstrates that RNA matchmaking changes HOTAIR RNA structure. Genome-wide HOTAIR/PRC2 activity occurs at genes whose transcripts can make favorable RNA-RNA interactions with HOTAIR. We demonstrate that RNA-RNA matches of HOTAIR with target gene RNAs can relieve the inhibitory effect of a single lncRNA for PRC2 activity. Our work highlights an intrinsic switch that allows PRC2 activity in specific RNA contexts, which could explain how many lncRNAs work with PRC2.

biochemistry