Database Study on the Expression and Purification of Membrane Proteins.

Membrane proteins are crucial for biological processes, and many of them are important to drug targets. Understanding the three-dimensional structures of membrane proteins are essential to evaluate their bio-function and drug design. High-purity membrane proteins are important for structural determination. Membrane proteins have low yields and are difficult to purify because they tend to aggregate. We summarized membrane protein expression systems, vectors, tags, and detergents, which have deposited in the Protein Data Bank (PDB) in recent four-and-a-half years. Escherichia coli is the most expression system for membrane proteins, and HEK293 cells are the most commonly cell lines for human membrane protein expression. The most frequently vectors are pFastBac1 for alpha-helical membrane proteins, pET28a for beta-barrel membrane proteins, and pTRC99a for monotopic membrane proteins. The most used tag for membrane proteins is the 6×His-tag. FLAG commonly used for alpha-helical membrane proteins, Strep and GST for beta- barrel and monotopic membrane proteins, respectively. The detergents and their concentrations used for alpha-helical, beta-barrel, and monotopic membrane proteins are different, and DDM is commonly used for membrane protein purification. It can guide the expression and purification of membrane proteins, thus contributing to their structure and bio function studying.

A novel gene mutation of Runx2 in cleidocranial dysplasia.

Haploinsufficiency of the runt-related transcription factor 2 (Runx2) gene is widely known to be responsible for cleidocranial dysplasia (CCD). To date, more than 190 mutations in Runx2 gene have been reported to be related to CCD. In this study, a novel mutation of Runx2 gene was observed in a female with CCD. Genomic DNA was extracted from peripheral venous blood of the proband and eleven members of her family. Genetic testing on these twelve people identified a novel missense mutation (c.895 T>C, Y299H) in exon 5 of the RUNX2 gene in the proband. This mutation results in an amino acid change at codon 895 (P.Tyr 299 His.) from a tryptophan codon (TAT) to a histidine codon (CAT). Our finding may further extend the known mutation spectrum of the RUNX2 gene, and facilitate prenatal genetic diagnosis of CCD in the future.

A Novel Gene Mutation of Runx2 in Cleidocranial Dysplasia / 华中科技大学学报（医学）（英德文版）

Haploinsuffieiency of the runt-related transcription factor 2 (Runx2) gene is widely known to be responsible for cleidocranial dysplasia (CCD).To date,more than 190 mutations in Runx2 gene have been reported to be related to CCD.In this study,a novel mutation of Runx2 gene was observed in a female with CCD.Genomic DNA was extracted from peripheral venous blood of the proband and eleven members of her family.Genetic testing on these twelve people identified a novel missense mutation (c.895T＞C,Y299H) in exon 5 of the RUNX2 gene in the proband.This mutation results in an amino acid change at codon 895 (P.Tyr 299 His.) from a tryptophan codon (TAT) to a histidine codon (CAT).Our finding may further extend the known mutation spectrum of the RUNX2 gene,and facilitate prenatal genetic diagnosis of CCD in the future.

The effect of SIRT6 on the odontoblastic potential of human dental pulp cells.

INTRODUCTION: The aim of this study was to investigate whether SIRT6 is expressed in human dental pulp as well as the effect of SIRT6 on proliferation and odontoblastic differentiation of human dental pulp cells (HDPCs). METHODS: Immunohistochemical and immunocytochemical assays were used to detect the expression of SIRT6 in human dental pulp tissue and HDPCs. To determine the effect of SIRT6 on odontoblast differentiation, HDPCs with loss (HDPCs SIRT6 knockdown) and gain (HDPCs SIRT6 overexpression) of SIRT6 function were developed, and their proliferation ability was examined. Odontogenic differentiation of HDPCs was determined by alkaline phosphatase (ALP) activity, ALP-positive cell staining, alizarin red staining, and von Kossa staining. Mineralization-related genes, including ALP, dentin sialophosphoprotein (DSPP), and dentin matrix acidic phosphoprotein 1, were determined by real-time quantitative polymerase chain reaction. Western blot analysis was performed to detect the expression of DSPP protein. RESULTS: SIRT6 was found in the dental pulp tissue and HDPCs. SIRT6 knockdown decreased ALP activity in HDPCs; calcium nodule formation ability; and the expression of mineralization-related genes such as ALP, DSPP, and DMP1, whereas these were increased with the overexpression of SIRT6. CONCLUSIONS: SIRT6 is expressed in human dental pulp and participates in the odontoblast differentiation of HDPCs.