H2A.Z is a highly conserved histone variant in all species. The chromatin deposition of H2A.Z is specifically catalyzed by the yeast chromatin remodeling complex SWR1 and its mammalian counterpart SRCAP. However, the mechanism by which H2A.Z is preferentially recognized by non-histone proteins remains elusive. Here we identified Anp32e, a novel higher eukaryote-specific histone chaperone for H2A.Z. Anp32e preferentially associates with H2A.Z-H2B dimers rather than H2A-H2B dimers in vitro and in vivo and dissociates non-nucleosomal aggregates formed by DNA and H2A-H2B. We determined the crystal structure of the Anp32e chaperone domain (186-232) in complex with the H2A.Z-H2B dimer. In this structure, the region containing Anp32e residues 214-224, which is absent in other Anp32 family proteins, specifically interacts with the extended H2A.Z αC helix, which exhibits an unexpected conformational change. Genome-wide profiling of Anp32e revealed a remarkable co-occupancy between Anp32e and H2A.Z. Cells overexpressing Anp32e displayed a strong global H2A.Z loss at the +1 nucleosomes, whereas cells depleted of Anp32e displayed a moderate global H2A.Z increase at the +1 nucleosomes. This suggests that Anp32e may help to resolve the non-nucleosomal H2A.Z aggregates and also facilitate the removal of H2A.Z at the +1 nucleosomes, and the latter may help RNA polymerase II to pass the first nucleosomal barrier.

Due to the well-known endocrine disrupting ability of bisphenol A (BPA), its production and usage have been regulated. Consequently, other bisphenol analogues (BPs) have been used as the replacement of BPA. Despite their widespread use, few studies have investigated the occurrence and fate of BPs in wastewater treatment plants (WWTPs). In this study, we conducted a city-wide monitoring survey and collected the wastewater and sludge samples from seven WWTPs in Xiamen, China over seven days. The concentrations of dissolved and adsorbed BPs in the influent and effluent, together with the BP concentrations in the sludge were determined. Five BPs, including BPA, BPAF, BPE, BPF, and BPS, were widely detected. The medium concentrations of BPA, BPAF, BPE, BPF, and BPS were 1318, 0.282, 3.70, 50.0, and 48.0 ng/L in the influent, 177, 0.714, 3.64, BLD, and BLD in the effluent, and 343, 3.09, BLD, 56.5, 1.01 μg/kg in the sludge. Spatial variations were observed, which implied the industrial origin of BPA. The efficiencies of BP removal from aqueous phase were evaluated, and results showed that BPA, BPF, and BPS were highly removed with removal efficiencies higher than 78%, while BPAF and BPE were resistant in WWTPs. Mass load calculations showed that 2075 g BPs entered into the WWTPs in Xiamen City each day, while 246 g and 63 g were discharged via effluent and excess sludge, respectively. Mass balance analysis showed that BPS and BPA were mainly biodegraded, BPF were mainly adsorbed and biodegraded, BPAF was resistant to biodegradation, while BPE was resistant to both biodegradation and adsorption.

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