Rabbit Anti-Human WDR77 Polyclonal Antibody

Histone post-translational modifications regulate chromatin structure and function largely through interactions with effector proteins that often contain multiple histone-binding domains. PHF1 [plant homeodomain (PHD) finger protein 1], which contains two kinds of histone reader modules, a Tudor domain and two PHD fingers, is an essential factor for epigenetic regulation and genome maintenance. While significant progress has been made in characterizing the function of the Tudor domain, the roles of the two PHD fingers are poorly defined. Here, we demonstrated that the N-terminal PHD finger of PHF1 recognizes symmetric dimethylation of H4R3 (H4R3me2s) catalyzed by PRMT5-WDR77. However, the C-terminal PHD finger of PHF1, instead of binding to modified histones, directly interacts with DDB1, the main component of the CUL4B-Ring E3 ligase complex (CRL4B), which is responsible for H2AK119 mono-ubiquitination (H2AK119ub1). We showed that PHF1, PRMT5-WDR77, and CRL4B reciprocally interact with one another and collaborate as a functional unit. Genome-wide analysis of PHF1/PRMT5/CUL4B targets identified a cohort of genes including E-cadherin and FBXW7, which are critically involved in cell growth and migration. We demonstrated that PHF1 promotes cell proliferation, invasion, and tumorigenesis in vivo and in vitro and found that its expression is markedly upregulated in a variety of human cancers. Our data identified a new reader for H4R3me2s and provided a molecular basis for the functional interplay between histone arginine methylation and ubiquitination. The results also indicated that PHF1 is a key factor in cancer progression, supporting the pursuit of PHF1 as a target for cancer therapy.

During lung development, cells proliferate for a defined length of time before they begin to differentiate. Factors that control this proliferative process and how this growth process is related to lung cancer are currently unknown. Here, we found that the WD40-containing protein (p44/wdr77) was expressed in growing epithelial cells at the early stages of lung development. In contrast, p44/wdr77 expression was diminished in fully differentiated epithelial cells in the adult lung. Loss of p44/wdr77 gene expression led to cell growth arrest and differentiation. Re-expression of p44/wdr77 caused terminally differentiated cells to re-enter the cell cycle. Our findings suggest that p44/wdr77 is essential and sufficient for proliferation of lung epithelial cells. P44/Wdr77 was re-expressed in lung cancer, and silencing p44/wdr77 expression strongly inhibited growth of lung adenocarcinoma cells in tissue culture and abolished growth of lung adenocarcinoma tumor xenografts in mice. The growth arrest induced by loss of p44/wdr77 expression was partially through the p21-Rb signaling. Our results suggest that p44/wdr77 controls cellular proliferation during lung development, and this growth process is reactivated during lung tumorigenesis. Oncogene (2013) 32, 1888-1900; doi:10.1038/onc.2012.207; published online 4 June 2012