FAM46B is a prokaryotic-like cytoplasmic poly(A) polymerase essential in human embryonic stem cells.

Family with sequence similarity (FAM46) proteins are newly identified metazoan-specific poly(A) polymerases (PAPs). Although predicted as Gld-2-like eukaryotic non-canonical PAPs, the detailed architecture of FAM46 proteins is still unclear. Exact biological functions for most of FAM46 proteins also remain largely unknown. Here, we report the first crystal structure of a FAM46 protein, FAM46B. FAM46B is composed of a prominently larger N-terminal catalytic domain as compared to known eukaryotic PAPs, and a C-terminal helical domain. FAM46B resembles prokaryotic PAP/CCA-adding enzymes in overall folding as well as certain inter-domain connections, which distinguishes FAM46B from other eukaryotic non-canonical PAPs. Biochemical analysis reveals that FAM46B is an active PAP, and prefers adenosine-rich substrate RNAs. FAM46B is uniquely and highly expressed in human pre-implantation embryos and pluripotent stem cells, but sharply down-regulated following differentiation. FAM46B is localized to both cell nucleus and cytosol, and is indispensable for the viability of human embryonic stem cells. Knock-out of FAM46B is lethal. Knock-down of FAM46B induces apoptosis and restricts protein synthesis. The identification of the bacterial-like FAM46B, as a pluripotent stem cell-specific PAP involved in the maintenance of translational efficiency, provides important clues for further functional studies of this PAP in the early embryonic development of high eukaryotes.

Wave-shaped microfluidic chip assisted point-of-care testing for accurate and rapid diagnosis of infections.

BACKGROUND: Early diagnosis and classification of infections increase the cure rate while decreasing complications, which is significant for severe infections, especially for war surgery. However, traditional methods rely on laborious operations and bulky devices. On the other hand, point-of-care (POC) methods suffer from limited robustness and accuracy. Therefore, it is of urgent demand to develop POC devices for rapid and accurate diagnosis of infections to fulfill on-site militarized requirements. METHODS: We developed a wave-shaped microfluidic chip (WMC) assisted multiplexed detection platform (WMC-MDP). WMC-MDP reduces detection time and improves repeatability through premixing of the samples and reaction of the reagents. We further combined the detection platform with the streptavidin-biotin (SA-B) amplified system to enhance the sensitivity while using chemiluminescence (CL) intensity as signal readout. We realized simultaneous detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) on the detection platform and evaluated the sensitivity, linear range, selectivity, and repeatability. Finally, we finished detecting 15 samples from volunteers and compared the results with commercial ELISA kits. RESULTS: Detection of CRP, PCT, and IL-6 exhibited good linear relationships between CL intensities and concentrations in the range of 1.25-40 µg/ml, 0.4-12.8 ng/ml, and 50-1600 pg/ml, respectively. The limit of detection of CRP, PCT, and IL-6 were 0.54 µg/ml, 0.11 ng/ml, and 16.25 pg/ml, respectively. WMC-MDP is capable of good adequate selectivity and repeatability. The whole detection procedure takes only 22 min that meets the requirements of a POC device. Results of 15 samples from volunteers were consistent with the results detected by commercial ELISA kits. CONCLUSIONS: WMC-MDP allows simultaneous, rapid, and sensitive detection of CRP, PCT, and IL-6 with satisfactory selectivity and repeatability, requiring minimal manipulation. However, WMC-MDP takes advantage of being a microfluidic device showing the coefficients of variation less than 10% enabling WMC-MDP to be a type of point-of-care testing (POCT). Therefore, WMC-MDP provides a promising alternative to POCT of multiple biomarkers. We believe the practical application of WMC-MDP in militarized fields will revolutionize infection diagnosis for soldiers.

Bidirectional regulation of angiogenesis by phytoestrogens through estrogen receptor-mediated signaling networks.

Sex hormone estrogen is one of the most active intrinsic angiogenesis regulators; its therapeutic use has been limited due to its carcinogenic potential. Plant-derived phytoestrogens are attractive alternatives, but reports on their angiogenic activities often lack in-depth analysis and sometimes are controversial. Herein, we report a data-mining study with the existing literature, using IPA system to classify and characterize phytoestrogens based on their angiogenic properties and pharmacological consequences. We found that pro-angiogenic phytoestrogens functioned predominantly as cardiovascular protectors whereas anti-angiogenic phytoestrogens played a role in cancer prevention and therapy. This bidirectional regulation were shown to be target-selective and, for the most part, estrogen-receptor-dependent. The transactivation properties of ERα and ERß by phytoestrogens were examined in the context of angiogenesis-related gene transcription. ERα and ERß were shown to signal in opposite ways when complexed with the phytoestrogen for bidirectional regulation of angiogenesis. With ERα, phytoestrogen activated or inhibited transcription of some angiogenesis-related genes, resulting in the promotion of angiogenesis, whereas, with ERß, phytoestrogen regulated transcription of angiogenesis-related genes, resulting in inhibition of angiogenesis. Therefore, the selectivity of phytoestrogen to ERα and ERß may be critical in the balance of pro- or anti-angiogenesis process.