Construction and Identification of Mammary Gland-specific Expression Vector of Bovine Tracheal Antimicrobial Peptide (TAP)

[ Objective] This study aimed to construct nmnmm_ry gland-specific expression vector of bovine tracheal antimicrobial peptide （TAP） gene. [ Method] TAP gene of dairy cattle was amplified from the mammary gland tissue by RT-PCR using a pair of primers which were designed according to bovine TAP cDNA se- quence （NM_174776） in GenBank, and then cloned into pMD19-T Simple vector for sequencing. The recombinant plasmid was digested using EcoRI and KpnI, the target gene fragment was recovered and inserted into general mammary gland-specific expression vector pBLG-EGFP harboring enhanced green fluorescent protein （ EGFP）, and transfected into bovine mammary epithelial cells （bMEC）, COS-7 cells and lactating rabbit mmmnary gland tissue by lipofectin transfection. The ex- pression of green fluorescent protein in transfected cells was detected under fluorescence microscopy, and the expression of TAP mRNA in rabbit mammary gland tis- sue was detected by semi-quantity RT-PCR. [ Result] The constructed mammary gland-specific expression vector pBLG-EGFP-TAP specifically expressed EGFP in transfected bMECs. In addition, semi-quantitative RT-PCR result showed that the expression level of TAP mRNA in rabbit mammary gland tissue was significantly enhanced after transfeeted with pBLG-EGFP-TAP. [ Conclusion] The mammary gland-specific expression vector pBLG-EGFP-TAP was successfully constructed, which provided important materials for further investigation of expression characteristics of TAP gene and prevention of bovine mastitis by using genetic engineering technology.

Exploring the catalytic function and active sites of a novel C-glycosyltransferase from Anemarrhena asphodeloides

Anemarrhena asphodeloides is an immensely popular medicinal herb in China,which contains an abundant of mangiferin.As an important bioactive xanthone C-glycoside,mangiferin possesses a variety of pharmacological activities and is derived from the cyclization reaction of a benzophenone C-glycoside(maclurin).Biosyntheti-cally,C-glycosyltransferases are critical for the formation of benzophenone C-glycosides.However,the benzo-phenone C-glycosyltransferases from Anemarrhena asphodeloides have not been discovered.Herein,a promiscuous C-glycosyltransferase(AaCGT)was identified from Anemarrhena asphodeloides.It was able to catalyze efficiently mono-C-glycosylation of benzophenone,together with di-C-glycosylation of dihydrochalcone.It also exhibited the weak O-glycosylation or potent S-glycosylation capacities toward 12 other types of flavonoid scaffolds and a simple aromatic compound with–SH group.Homology modeling and mutagenesis experiments revealed that the glycosylation reaction of AaCGT was initiated by the conserved residue H23 as the catalytic base.Three critical residues H356,W359 and D380 were involved in the recognition of sugar donor through hydrogen-bonding interactions.In particular,the double mutant of F94W/L378M led to an unexpected enzy-matic conversion of mono-C-to di-C-glycosylation.This study highlights the important value of AaCGT as a potential biocatalyst for efficiently synthesizing high-value C-glycosides.

Fully synthetic Tn-based three-component cancer vaccine using covalently linked TLR4 ligand MPLA and iNKT cell agonist KRN-7000 as built-in adjuvant effectively protects mice from tumor development

We present a new strategy for self-adjuvanting vaccine development that has different types of covalently-linked immunostimulants as the carrier molecule.Using Tn antigen as the model,a three-component vaccine(MPLA-Tn-KRN7000)containing the TLR4 ligand MPLA and the iNKT cell agonist KRN7000 was designed and synthesized.This expands fully synthetic self-adjuvanting vaccine studies that use a single carrier to one with two different types of carriers.The corresponding two-component conjugate vaccines Tn-MPLA,Tn-KRN7000 and Tn-CRM197 were also synthesized,as controls.The immunological evaluation found that MPLA-Tn-KRN7000 elicits robust Tn-specific and T cell-dependent immunity.The antibodies specifically recognized,bound to and exhibited complement-dependent cytotoxicity against Tn-positive cancer cells.In addition,MPLA-Tn-KRN7000 increased the survival rate and survival time of tumor-challenged mice,and surviving mice reject further tumor attacks without any additional treatment.Compared to the glycoprotein vaccine Tn-CRM197,the two-component conjugate vaccines,Tn-MPLA and Tn-KRN7000,and the physical mixture of Tn-MPLA and Tn-KRN7000,MPLA-Tn-KRN7000 showed the most effect at combating tumor cells both in vitro and in vivo.The comparison of immunological studies in wild-type and TLR4 knockout mice,along with the test of binding affinity to CD1d protein suggests that the covalently linked MPLA-KRN7000 immunostimulant induces a synergistic activation of TLR4 and iNKT cell that improves the immunogenicity of Tn.This work demonstrates that MPLA-Tn-KRN7000 has the potential to be a vaccine candidate and provides a new direction for fully synthetic vaccine design.

LncRNAs are involved in regulating ageing and age-related disease through the adenosine monophosphate-activated protein kinase signalling pathway

A long noncoding RNA(lncRNA)is longer than 200 bp.It regulates various biological processes mainly by interacting with DNA,RNA,or protein in multiple kinds of biological processes.Adenosine monophosphate-activated protein kinase(AMPK)is activated during nutrient starvation,especially glucose starvation and oxygen deficiency(hypoxia),and exposure to toxins that inhibit mitochondrial respiratory chain complex function.AMPK is an energy switch in organisms that controls cell growth and multiple cellular processes,including lipid and glucose metabolism,thereby maintaining intracellular energy homeostasis by activating catabolism and inhibiting anabolism.The AMPK signalling pathway consists of AMPK and its upstream and downstream targets.AMPK upstream targets include proteins such as the transforming growth factor b-activated kinase 1(TAK1),liver kinase B1(LKB1),and calcium/calmodulindependent protein kinase b(CaMKKb),and its downstream targets include proteins such as the mechanistic/mammalian target of rapamycin(mTOR)complex 1(mTORC1),hepatocyte nuclear factor 4a(HNF4a),and silencing information regulatory 1(SIRT1).In general,proteins function relatively independently and cooperate.In this article,a review of the currently known lncRNAs involved in the AMPK signalling pathway is presented and insights into the regulatory mechanisms involved in human ageing and age-related diseases are provided.