p-coumaric acid is an important natural phenolic compound with a variety of pharmacological activities, and also a precursor for the biosynthesis of many natural compounds. It is widely used in foods, cosmetics and medicines. Compared with the chemical synthesis and plant extraction, microbial production of p-coumaric acid has many advantages, such as energy saving and emission reduction. However, the yield of p-coumaric acid by microbial synthesis is too low to meet the requirements of large-scale industrial production. Here, to further improve p-coumaric acid production, the directed evolution of tyrosine ammonia lyase (TAL) encoded by Rhodotorula glutinis tal gene was conducted, and a high-throughput screening method was established to screen the mutant library for improve the property of TAL. A mutant with a doubled TAL catalytic activity was screened from about 10,000 colonies of the mutant library. There were three mutational amino acid sites in this TAL, namely S9Y, A11N, and E518A. It was further verified by a single point saturation mutation. When S9 was mutated to Y, I or N, or A11 was mutated to N, T or Y, the catalytic activity of TAL increased by more than 1-fold. Through combinatorial mutation of three types of mutations at the S9 and A11, the TAL catalytic activity of S9Y/A11N or S9N/A11Y mutants were significantly higher than that of other mutants. Then, the plasmid containing S9N/A11Y mutant was transformed into CP032, a tyrosine-producing E. coli strain. The engineered strain produced 394.2 mg/L p-coumaric acid, which is 2.2-fold higher than that of the control strain, via shake flask fermentation at 48 h. This work provides a new insight for the biosynthesis study of p-coumaric acid.
Ammonia-Lyases/genetics* ; Escherichia coli/genetics* ; Propionates ; Rhodotorula ; Tyrosine/genetics*

Tyrosine is an important aromatic amino acid. Besides its nutritional value, tyrosine is also an important precursor for the synthesis of coumarins and flavonoids. Previously, our laboratory constructed a Saccharomyces cerevisiae strain LTH0 (ARO4K229L, ARO7G141S, Δaro10, Δzwf1, Δura3) where tyrosine feedback inhibition was released. In the present study, heterologous expression of betaxanthins synthesis genes DOD (from Mirabilis jalapa) and CYP76AD1 (from sugar beet B. vulgaris) in strain LTH0 enabled production of yellow fluorescence. The engineered strain LTH0-DOD-CYP76AD1 was subjected to UV combined with ARTP mutagenesis, followed by flow cytometry screening. Among the mutants screened, the fluorescence intensity of the mutant strain LTH2-5-DOD-CYP76AD1 at the excitation wavelength of 485 nm and emission wavelength of 505 nm was (5 941±435) AU/OD, which was 8.37 times higher than that of strain LTH0-DOD-CYP76AD1. Fourteen mutant strains were subjected to fermentation to evaluate their tyrosine producing ability. The highest extracellular tyrosine titer reached 26.8 mg/L, which was 3.96 times higher than that of strain LTH0-DOD-CYP76AD1. Heterologous expression of the tyrosine ammonia lyase FjTAL derived from Flavobacterium johnsoniae further increased the titer of coumaric acid to 119.8 mg/L, which was 1.02 times higher than that of the original strain LTH0-FjTAL.
Flavobacterium ; High-Throughput Screening Assays ; Mirabilis ; Saccharomyces cerevisiae/genetics* ; Tyrosine

p-coumaric acid is one of the aromatic compounds that are widely used in food, cosmetics and medicine due to its properties of antibacterium, antioxidation and cardiovascular disease prevention. Tyrosine ammonia-lyase (TAL) catalyzes the deamination of tyrosine to p-coumaric acid. However, the lack of highly active and specific tyrosine ammonia lyase limits cost-effective microbial production of p-coumaric acid. In order to improve biosynthesis efficiency of p-coumaric acid, two tyrosine ammonia-lyases, namely Fc-TAL2 derived from Flavobacterium columnare and Fs-TAL derived from Flavobacterium suncheonense, were selected and characterized. The optimum temperature (55 ℃) and pH (9.5) for Fs-TAL and Fc-TAL2 are the same. Under optimal conditions, the specific enzyme activity of Fs-TAL and Fc-TAL2 were 82.47 U/mg and 13.27 U/mg, respectively. Structural simulation and alignment analysis showed that the orientation of the phenolic hydroxyl group of the conserved Y50 residue on the inner lid loop and its distance to the substrate were the main reasons accounting for the higher activity of Fs-TAL than that of Fc-TAL2. The higher activity and specificity of Fs-TAL were further confirmed via whole-cell catalysis using recombinant Escherichia coli, which could convert 10 g/L tyrosine into 6.2 g/L p-coumaric acid with a yield of 67.9%. This study provides alternative tyrosine ammonia-lyases and may facilitate the microbial production of p-coumaric acid and its derivatives.
Ammonia-Lyases/chemistry* ; Coumaric Acids ; Escherichia coli/genetics* ; Tyrosine

Adolescent ; Fucosyltransferases ; genetics ; Gene Rearrangement ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Male ; Protein-Tyrosine Kinases ; genetics

OBJECTIVETo investigate the clinical characteristics of newly diagnosed acute myeloid leukemia (AML) with NPM1 mutation.

METHODSNPM1 mutation (including A, B, D mutation type) was detected in 206 patients with newly diagnosed AML by real-time quantitative RT-PCR.

RESULTSThe incidence of NPM1 mutation was 15.5% in total AML patients and 32.5% in normal karyotypes AML patients. The characteristics of 174 NPM1 wild type patients v.s. that of 32 NPM1 mutation patients was as follow, median age (46 vs 35 years old, P < 0.01), WBC counts (27 × 10(9)/L vs 8 × 10(9)/L, P < 0.01), BPC (82 × 10(9)/L vs 36 × 10(9)/L, P < 0.01), proportion of AML-M(5) (31.2% vs 5.8%, P = 0.01), incidence of normal karyotypes (92.6% vs 40.8%, P < 0.01), incidence of FLT3-ITD-positive (25.0% vs 7.5%, P < 0.01), CD34-positvie (23.3% vs 69.5%, P < 0.01), cases with fusion gene (0 vs 47.1%, P < 0.01). No statistic difference was found in sex, percentage of blasts in bone marrow, complete remission rate, overall survival between the two groups. Relapse-free survival in AML patients with NPM1-mutation and FLT3-ITD-negative tended to be higher than in those with NPM1-mutation and FLT3-ITD-positive.

CONCLUSIONIt is necessary to detect NPM1 mutation and FLT3-ITD in newly diagnosed AML patients, especially in patients with high WBC and BPC, CD34-negative, normal karyotype, which might help to molecular classification and treatment.

Humans ; Leukemia, Myeloid, Acute ; genetics ; Mutation ; Nuclear Proteins ; genetics ; Prognosis ; fms-Like Tyrosine Kinase 3 ; genetics

OBJECTIVE: To investigate the clinical features, accompanying gene mutation characteristics and prognostic factors of adult patients with acute myeloid leukemia with mutated NPM1 (NPM1AML). METHODS: Seventy-three patients with newly diagnosed adult NPM1AML were selected. The mutations of 22 genes were detected by second generation sequencing and 43 fusion genes of AML were detected by real-time fluorescent quantitative PCR. The Kaplan-Meier survival curve and Cox multivariate regression analysis were used to study the prognostic factors. RESULTS: A total of 74 NPM1 site mutations were detected in 73 patients with NPM1AML. The incidence rates were 92.0% L287fs, 2.7% Q289fs and W288fs, 1.4% L258fs and Q289H, among which 1 patient had 2 NPM1 mutations; the different mutation sites had no effect on the prognosis of NPM1AML. The median value of NPM1 variant allele frequency (VAF) was 35.4% (1.8%-56.6%). Based on the uppermost quartile of 38.4%, the patients were classified as NPM1 VAF>38.4% (NPM1AML) and NPM1 VAF≤38.4% (NPM1AML). Compared with NPM1AML, the early mortality rate was statistically significantly higher (33.3% vs 7.3%, P<0.05), and median EFS (148 d，95%CI 58-238 d vs 372 d，95%CI 264-480 d) (P<0.01) and median OS (179 d 95%CI 6-352 d vs 444 d) (P<0.01) were significantly shorter in NPM1 AML. A total of 126 accompanying gene mutation sites were detected in 87.7% of patients with NPM1AML. The patients with NRAS gene mutation displayed a higher rate of complete remission (100% vs 58%) (P<0.05) and longer median OS (not reached to 320 d, 95%CI 150-490 d) (P<0.05). The 43 fusion genes were examined in 65 out of 73 cases of NPM1AML, and in all the patients the fusion gene test was negative. Multivariate analysis showed that NPM1 VAF>38.4% was an independent prognostic factor for EFS (HR=3.1, 95% CI 1.6-6.4, P<0.01) and OS (HR=3.0, 95% CI 1.4-6.2, P<0.01). CONCLUSION The NPM1 gene mutation in AML patients often is accompanied by other gene mutations, while the coexistence of fusion genes is rare; high NPM1 mutant allele burden is an independent prognostic factor for adult AML patients with mutated NPM1.
Alleles ; Humans ; Leukemia, Myeloid, Acute ; genetics ; Mutation ; Nuclear Proteins ; genetics ; Prognosis ; fms-Like Tyrosine Kinase 3

OBJECTIVE: To explore the genetic pathogenesis of X-linked agammaglobulinemia in two patients for clinical diagnosis and family counseling. METHODS: Data was collected from the patients' family including clinical information, blood immunoglobulin level, as well as classification and subgrouping of B lymphocytes. Gene mutations were screened by whole exome sequencing (WES) through next-generation sequencing (NGS), the result was verified with Sanger sequencing. RESULTS: A BTK c.1627T>C (p.Ser543Pro) variant was found in the pedigree. The phenotype and variant have co-segregated in the pedigree. The variant was not found in population database. The variant has affected in the kinase domain which contained no benign variants and is harmful as predicted through bioinformatic analysis. CONCLUSION BTK c.1627T>C (p.Ser543Pro) is a pathogenic variant contributing to X-linked agammaglobulinemia in this pedigree. Above finding has provided reproduction guidance for this family.
Agammaglobulinaemia Tyrosine Kinase/genetics* ; Agammaglobulinemia/genetics* ; DNA Mutational Analysis ; Genetic Diseases, X-Linked ; Humans ; Mutation ; Pedigree

The aim of study was to investigate the killing effect of double suicide gene system mediated by retroviral vector on K562 cells in vivo and ex vivo. CDglyTK gene was transfected into PA317 cells by using lipofectamine. K562 cells were infected with viral supernatant. K562/CDglyTK cells were treated with 5-fluorocytosine (5-FC) and/or ganciclovir (GCV). Mice were randomly divided into three groups: tumor formation, tumor inhibition and tumor therapy. Each mouse was implanted with K562/CDglyTK cells or K562 cells. The results indicated that the killing effect of 5-FC in combination with GCV on K562/CDglyTK was more significant than using 5-FC or GCV alone. In vivo study showed that after being injected subcutaneously with K562 cells and K562/CDglyTK cells, there was not obvious difference in tumor formation rate of mice, 5-FC + GCV could suppress tumor formation of the K562/CDglyTK cells. After being treated with 5-FC and GCV, the median tumor volume of mice implanted with K562/CDglyTK cells decreased obviously, compared with the control group. Their median survival was significantly prolonged. It is concluded that double suicide genes are more effective for killing effect on K562 cells in vivo and in ex vivo. It may be applicable to clinical gene therapy.
Cytosine Deaminase ; genetics ; Flucytosine ; pharmacology ; Ganciclovir ; pharmacology ; Genes, Transgenic, Suicide ; genetics ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; K562 Cells ; Protein-Tyrosine Kinases ; genetics ; Receptor Protein-Tyrosine Kinases ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; genetics ; Recombination, Genetic ; Retroviridae ; genetics

OBJECTIVETo compare the value of fluorescence in situ hybridization(FISH) with that of immunohistochemistry in detecting ALK gene translocations and ALK fusion protein in anaplastic large cell lymphoma (ALCL) and investigate the possibility of FISH working on paraffin-embedded ALCL tissue.

METHODSDual-color FISH and ALK-1 immunohistochemistry were used to detect ALK gene translocation and ALK fusion protein in 22 paraffin-embedded ALCL cases.

RESULTSThe digestion time of tissue section was a key-point in the operating of FISH in paraffin-embedded tissue. ALK fusion protein expression was detected with ALK-1 antibody in 12 of the 20 systemic ALCL; it was not detected in 2 primary cutaneous ALCL. The Dual-color FISH results were 100% consonant with the immunohistochemical results.

CONCLUSION(1) Generally, immunohistochemical method is the first choice in detecting ALK gene translocation, but when conditions permit, FISH can be the first choice. (2) By the optimization of experimental conditions, FISH can be successfully performed on paraffin-embedded tissue.

Humans ; In Situ Hybridization, Fluorescence ; methods ; Lymphoma, Large-Cell, Anaplastic ; genetics ; pathology ; Paraffin Embedding ; methods ; Protein-Tyrosine Kinases ; genetics ; Receptor Protein-Tyrosine Kinases ; Reproducibility of Results ; Translocation, Genetic

Mer is one member of Axl receptor tyrosine kinase family, and its ligand Gas6 can stimulate activity of Mer receptor tyrosine kinase after binding it, and then activate the downstream signal transduction pathway, Mer participates in cell inflammation, apoptosis, tumorigenesis, thrombosis and hemostasis. Rencet advances of study on Mer function were reviewed, and its potential prospects of antithrombosis and antitumor were discussed in this article.
Animals ; Fibrinolytic Agents ; Humans ; Intercellular Signaling Peptides and Proteins ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Receptor Protein-Tyrosine Kinases ; genetics ; metabolism ; Signal Transduction ; c-Mer Tyrosine Kinase