Attenuation of pre-rRNA synthesis in response to elevated temperature is accompanied by increased levels of PAPAS ("promoter and pre-rRNA antisense") a long noncoding RNA (lncRNA) that is transcribed in an orientation antisense to pre-rRNA. Here we show that PAPAS interacts directly with DNA, forming a DNA-RNA triplex structure that tethers PAPAS to a stretch of purines within the enhancer region, thereby guiding associated CHD4/NuRD (nucleosome remodeling and deacetylation) to the rDNA promoter. Protein-RNA interaction experiments combined with RNA secondary structure mapping revealed that the N-terminal part of CHD4 interacts with an unstructured A-rich region in PAPAS. Deletion or mutation of this sequence abolishes the interaction with CHD4. Stress-dependent up-regulation of PAPAS is accompanied by dephosphorylation of CHD4 at three serine residues, which enhances the interaction of CHD4/NuRD with RNA and reinforces repression of rDNA transcription. The results emphasize the function of lncRNAs in guiding chromatin remodeling complexes to specific genomic loci and uncover a phosphorylation-dependent mechanism of CHD4/NuRD-mediated transcriptional regulation.

The human FACT (facilitates chromatin transcription) complex, composed of two subunits SPT16 (Suppressor of Ty 16) and SSRP1 (Structure-specific recognition protein-1), plays essential roles in nucleosome remodeling. However, the molecular mechanism of FACT reorganizing the nucleosome still remains elusive. In this study, we demonstrate that FACT displays dual functions in destabilizing the nucleosome and maintaining the original histones and nucleosome integrity at the single-nucleosome level. We found that the subunit SSRP1 is responsible for maintenance of nucleosome integrity by holding the H3/H4 tetramer on DNA and promoting the deposition of the H2A/H2B dimer onto the nucleosome. In contrast, the large subunit SPT16 destabilizes the nucleosome structure by displacing the H2A/H2B dimers. Our findings provide mechanistic insights by which the two subunits of FACT coordinate with each other to fulfill its functions and suggest that FACT may play essential roles in preserving the original histones with epigenetic identity during transcription or DNA replication.

Along with the massive use of implants in orthopaedic surgeries in recent few decades, there has been a tremendous demand for the surface modification of the implants to avoid surgery failure and improve their function. Polydopamine (PDA), being able to adhere to almost all kinds of substrates and possessing copious functional groups for covalently immobilizing biomolecules and anchoring metal ions, has been widely used for surface modification of materials since its discovery in the last decade. PDA and its derivatives can be used for the surface modification of orthopaedic implants to modulate cellular responses, including cell spreading, migration, proliferation, and differentiation, and may thereby enhance the function of existing implants. In addition, the osseointegration and antimicrobial properties of orthopaedic implants may also be improved by PDA-based coatings. The aim of this review is to provide a brief overview of current advances of surface modification technologies for orthopaedic implants using PDA and its derivatives as a medium. Given the versatility of PDA-based adhesion, such PDA-assisted surface modification technologies will certainly benefit the development of new orthopaedic implants. The translational potential of this article Surface treatments of orthopaedic implants, which are normally inert materials, are essential for their performance in vivo. This review summarizes recent advances in the surface modification of orthopaedic implants using facile and highly versatile techniques based on the use of polydopamine (PDA) and its derivatives.

To obtain more knowledge on the origin and genetic diversity of the swamp buffalo (Bubalus bubalis) in China, the complete mitochondrial D-loop sequences of 119 samples representing seven native types were compared. Two mitochondrial DNA (mtDNA) lineages (lineages A and B) were determined for the Chinese swamp buffalo. Examination of the diversity patterns suggest that lineage A has undergone a population expansion event. Divergence of lineages A and B was estimated at 18,000 years ago. Combined analyses of mtDNA sequences from Chinese, Indian, Brazilian/Italian and Southeast Asian/Australian buffalo samples showed independent domestication events in the swamp buffalo from China and the river buffalo from the India subcontinent. The spread of swamp and river buffalo from China and India respectively to mainland Southeast Asia suggests that Southeast Asia is a hybrid zone for buffalo. Our data support the hypothesis of the evolution of domesticated swamp and river buffalo from ancestral swamp-like animals. These ancestral animals were extensively distributed across mainland Asia and most likely are represented today by the wild Asian buffalo (Bubalus arnee).

Exploring innovative solutions to improve the healthcare of the aging and diseased population continues to be a global challenge. Among a number of strategies toward this goal, tissue engineering and regenerative medicine (TERM) has gradually evolved into a promising approach to meet future needs of patients. TERM has recently received increasing attention in Asia, as evidenced by the markedly increased number of researchers, publications, clinical trials, and translational products. This review aims to give a brief overview of TERM development in Asia over the last decade by highlighting some of the important advances in this field and featuring major achievements of representative research groups. The development of novel biomaterials and enabling technologies, identification of new cell sources, and applications of TERM in various tissues are briefly introduced. Finally, the achievement of TERM in Asia, including important publications, representative discoveries, clinical trials, and examples of commercial products will be introduced. Discussion on current limitations and future directions in this hot topic will also be provided.

The activity of rRNA genes (rDNA) is regulated by pathways that target the transcription machinery or alter the epigenetic state of rDNA. Previous work has established that downregulation of rRNA synthesis in quiescent cells is accompanied by upregulation of PAPAS, a long noncoding RNA (lncRNA) that recruits the histone methyltransferase Suv4-20h2 to rDNA, thus triggering trimethylation of H4K20 (H4K20me3) and chromatin compaction. Here, we show that upregulation of PAPAS in response to hypoosmotic stress does not increase H4K20me3 because of Nedd4-dependent ubiquitinylation and proteasomal degradation of Suv4-20h2. Loss of Suv4-20h2 enables PAPAS to interact with CHD4, a subunit of the chromatin remodeling complex NuRD, which shifts the promoter-bound nucleosome into the transcriptional "off" position. Thus, PAPAS exerts a "stress-tailored" dual function in rDNA silencing, facilitating either Suv4-20h2-dependent chromatin compaction or NuRD-dependent changes in nucleosome positioning.

Attenuation of ribosome biogenesis in suboptimal growth environments is crucial for cellular homeostasis and genetic integrity. Here, we show that shutdown of rRNA synthesis in response to elevated temperature is brought about by mechanisms that target both the RNA polymerase I (Pol I) transcription machinery and the epigenetic signature of the rDNA promoter. Upon heat shock, the basal transcription factor TIF-IA is inactivated by inhibition of CK2-dependent phosphorylations at Ser170/172. Attenuation of pre-rRNA synthesis in response to heat stress is accompanied by upregulation of PAPAS, a long non-coding RNA (lncRNA) that is transcribed in antisense orientation to pre-rRNA. PAPAS interacts with CHD4, the adenosine triphosphatase subunit of NuRD, leading to deacetylation of histones and movement of the promoter-bound nucleosome into a position that is refractory to transcription initiation. The results exemplify how stress-induced inactivation of TIF-IA and lncRNA-dependent changes of chromatin structure ensure repression of rRNA synthesis in response to thermo-stress.

We developed UAVNet, a framework for the autonomous deployment of a flying Wireless Mesh Network using small quadrocopter-based Unmanned Aerial Vehicles (UAVs). The flying wireless mesh nodes are automatically interconnected to each other and building an IEEE 802.11s wireless mesh network. The implemented UAVNet prototype is able to autonomously interconnect two end systems by setting up an airborne relay, consisting of one or several flying wireless mesh nodes. The developed software includes basic functionality to control the UAVs and to setup, deploy, manage, and monitor a wireless mesh network. Our evaluations have shown that UAVNet can significantly improve network performance.