Dense multicilia in higher vertebrates are important for luminal flow and the removal of thick mucus. To generate hundreds of basal bodies for multiciliogenesis, specialized terminally differentiated epithelial cells undergo massive centriole amplification. In proliferating cells, however, centriole duplication occurs only once per cell cycle. How cells ensure proper regulation of centriole biogenesis in different contexts is poorly understood. We report that the centriole amplification is controlled by two duplicated genes, Cep63 and Deup1. Cep63 regulates mother-centriole-dependent centriole duplication. Deup1 governs deuterosome assembly to mediate large-scale de novo centriole biogenesis. Similarly to Cep63, Deup1 binds to Cep152 and then recruits Plk4 to activate centriole biogenesis. Phylogenetic analyses suggest that Deup1 diverged from Cep63 in a certain ancestor of lobe-finned fishes during vertebrate evolution and was subsequently adopted by tetrapods. Thus, the Cep63 gene duplication has enabled mother-centriole-independent assembly of the centriole duplication machinery to satisfy different requirements for centriole number.

Cilia are cellular protrusions containing nine microtubule (MT) doublets and function to propel cell movement or extracellular liquid flow through beating or sense environmental stimuli through signal transductions. Cilia require the central pair (CP) apparatus, consisting of two CP MTs covered with projections of CP proteins, for planar strokes. How the CP MTs of such ‘9 + 2’ cilia are constructed, however, remains unknown. Here we identify Spef1, an evolutionarily conserved microtubule-bundling protein, as a core CP MT regulator in mammalian cilia. Spef1 was selectively expressed in mammalian cells with 9 + 2 cilia and specifically localized along the CP. Its depletion in multiciliated mouse ependymal cells by RNAi completely abolished the CP MTs and markedly attenuated ciliary localizations of CP proteins such as Hydin and Spag6, resulting in rotational beat of the ependymal cilia. Spef1, which binds to MTs through its N-terminal calponin-homologous domain, formed homodimers through its C-terminal coiled coil region to bundle and stabilize MTs. Disruption of either the MT-binding or the dimerization activity abolished the ability of exogenous Spef1 to restore the structure and functions of the CP apparatus. We propose that Spef1 bundles and stabilizes central MTs to enable the assembly and functions of the CP apparatus.

Mammalian epithelial cells use a pair of parental centrioles and numerous deuterosomes as platforms for efficient basal body production during multiciliogenesis. How deuterosomes form and function, however, remain controversial. They are proposed to arise either spontaneously for massive de novo centriole biogenesis or in a daughter centriole‐dependent manner as shuttles to carry away procentrioles assembled at the centriole. Here, we show that both parental centrioles are dispensable for deuterosome formation. In both mouse tracheal epithelial and ependymal cells (mTECs and mEPCs), discrete deuterosomes in the cytoplasm are initially procentriole‐free. They emerge at widely dispersed positions in the cytoplasm and then enlarge, concomitant with their increased ability to form procentrioles. More importantly, deuterosomes still form efficiently in mEPCs whose daughter centriole or even both parental centrioles are eliminated through shRNA‐mediated depletion or drug inhibition of Plk4, a kinase essential to centriole biogenesis in both cycling cells and multiciliated cells. Therefore, deuterosomes can be assembled autonomously to mediate de novo centriole amplification in multiciliated cells.

Prenatal alcohol exposure is associated with long-term changes in dendritic spines and synaptic ultrastructure; these alterations probably reflect the developmental retardation of dendritic spines and synapses in visual cortex. These long-term changes are likely to contribute to lifelong mental retardation associated with childhood FASDs.

Oxidation of methanol not only eliminates contamination due to typical volatile organic compounds (VOCs), but also provides clean energy.

Three-dimensional (3D) nanostructures assembled with one-or few-layered ultrathin two-dimensional (2D) crystals have triggered great interest in energy and environmental applications. Here, we introduce a gas-foaming process in an hexagonal boron nitride (h-BN) ceramic material to fabricate 3D white graphene (WG) foams without using any catalysts or templates for superstrong pollutant removal applications. Importantly, the introduction of vesicants guaranteed the reproducibility and yield (4500 cm 3 ). Interestingly, these 3D WG foams possessed a vesicular structure with hierarchical pores ranging from nm to μm scales and with ultrathin walls consisting of mono-or few-layered BN membranes with planar sizes as large as 100 μm. Consequently, such microstructure merits of hierarchical pores and ultrathin walls endowed them not only very low density (2.1 mg cm − 3 ) but also superstrong adsorption ability, illustrated by capacitances up to 190 times its own weight toward a wide range of environment contaminations, including various oils and dyes. Thus, the 3D h-BN WG foams prepared by vesicant-assisted foaming should have great potential as outstanding environmental scavengers. NPG Asia Materials (2015) 7, e168; doi:10.1038/am.2015.8; published online 27 March 2015 INTRODUCTION Two-dimensional (2D) crystals, such as graphene 1 and white graphene (WG, mono-or few-layered hexagonal boron nitride (h-BN)), 2,3 have triggered great interest because of their extraordinary intrinsic properties and wide range of applications in electronics, optoelectronics, energy storage and the environment. 4 However, for some specific applications, such as the adsorption of various contaminants and as electrodes in electrochemical cells, their pristine flat 2D structures have been recognized to not fully match the practical requirements. [5][6][7][8] In contrast, three-dimensional (3D) architectures using 2D crystals as building blocks can simultaneously provide the virtues of 2D and 3D structures, such as ultrathin sheets and large specific surface areas from 2D sheets 6 and hierarchical pores and ultralight densities from 3D configurations. 7 Recently, such novel 2D-3D structure features have been proven to exhibit new and outstanding performances. For instance, graphenecarbon nanotube 3D structures had densities as low as 0.16 mg cm − 3 , even lighter than air (1.29 mg cm − 3 ); 9 3D graphene and BN networks exhibited excellent mechanical properties; 10,11 3D BNC hybrid networks showed tunable electronic and thermal properties. 12 However, the high-yield fabrication of such 3D architectures of 2D crystals, especially without using any templates or catalysts, remains a great challenge. Currently, there are two methods for fabricating 3D

Centriole number is normally under tight control and is directly linked to ciliogenesis. In cells that use centrosomes as mitotic spindle poles, one pre-existing mother centriole is allowed to duplicate only one daughter centriole per cell cycle. In multiciliated cells, however, many centrioles are generated to serve as basal bodies of the cilia. Although deuterosomes were observed more than 40 years ago using electron microscopy and are believed to produce most of the basal bodies in a mother centriole-independent manner, the underlying molecular mechanisms have remained unknown until recently. From these findings arise more questions and a call for clarifications that will require multidisciplinary efforts.

No abstract