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Pre-rRNA processing is essential to ribosome biosynthesis. However, the processing mechanism is not fully understood in plants. Here, we report a DEAD-box RNA helicase DEK51 that mediates the 3′ end processing of 18S and 5.8S pre-rRNA in maize (Zea mays L.). DEK51 is localized in the nucleolus, and loss of DEK51 arrests maize seed development and blocks the 3′ end processing of 18S and 5.8S pre-rRNA. DEK51 interacts with putative key factors in nuclear RNA exosome-mediated pre-rRNA processing, including ZmMTR4, ZmSMO4, ZmRRP44A, and ZmRRP6L2. This suggests that DEK51 facilitates pre-rRNA processing by interacting with the exosome. Loss of ZmMTR4 function arrests seed development and blocks the 3′ end processing of 18S and 5.8S pre-rRNA, similar to dek51. DEK51 also interacts with endonucleases ZmUTP24 and ZmRCL1, suggesting that it may also be involved in the cleavage at site A2. These results show the critical role of DEK51 in promoting 3′ end processing of pre-rRNA. [Display omitted] • Dek51 encodes a DEAD-box RNA helicase essential for maize seed development • DEK51 mediates the 3′ end processing of 18S and 5.8S pre-rRNA • DEK51 interacts with key factors in the exosome-mediated pre-rRNA processing • DEK51 interacts with the putative endonucleases for A2 site processing of 18S pre-rRNA Wang et al. identify a crucial pre-rRNA processing factor DEK51, a DEAD-box RNA helicase whose loss of function causes embryo lethality in maize. DEK51 plays an essential role in the exosome-mediated 3′ end processing of 18S and 5.8S pre-rRNA via interacting with ZmMTR4, ZmSMO4, and other key accessory pre-rRNA processing factors. [ABSTRACT FROM AUTHOR]

Cellulose nanofiber templated Bi nanoparticles (CNF/nBi) were used as X-ray shielding additives for preparing UHMWPE porous membrane via the thermally induced phase separation (TIPS) method, which overcomes the defects of lacking air and water vapor permeability in current apron. CNF was synthesized by the TEMPO-oxidized method, and carboxylate groups were introduced on its surface, so Bi3+ could be bonded to the surface of CNF, and then reduced to Bi nanoparticles with a diameter of 4.4 nm. CNF/nBi were dispersed into decalin with the help of cationic surfactant CTAB, then the preweighed components (CNF/nBi, UHMWPE, decalin) passed through a twin-excluder. After that, UHMWPE/PM/CNF/nBi composite membranes were obtained by compressing the extrudate with a piece of polyester mesh (PM). The porous membranes have a good air and water vapor permeability as well as mechanical strength compared with Tyvek. The composite membranes also have a good shielding property for X-ray photon energy below 33 keV. Image 1 [ABSTRACT FROM AUTHOR]