In addition to DNA repair pathways, cells utilize translesion DNA synthesis (TLS) to bypass DNA lesions during replication. During TLS, Y-family DNA polymerase (Polη, Polκ, Polı and Rev1) inserts specific nucleotide opposite preferred DNA lesions, and then Polζ consisting of two subunits, Rev3 and Rev7, carries out primer extension. Here, we report the complex structures of Rev3-Rev7-Rev1(CTD) and Rev3-Rev7-Rev1(CTD)-Polκ(RIR). These two structures demonstrate that Rev1(CTD) contains separate binding sites for Polκ and Rev7. Our BIAcore experiments provide additional support for the notion that the interaction between Rev3 and Rev7 increases the affinity of Rev7 and Rev1. We also verified through FRET experiment that Rev1, Rev3, Rev7 and Polκ form a stable quaternary complex in vivo, thereby suggesting an efficient switching mechanism where the "inserter" polymerase can be immediately replaced by an "extender" polymerase within the same quaternary complex.
Binding Sites ; Crystallography, X-Ray ; DNA Repair ; DNA-Binding Proteins ; chemistry ; genetics ; metabolism ; DNA-Directed DNA Polymerase ; chemistry ; genetics ; metabolism ; Fluorescence Resonance Energy Transfer ; Humans ; Mad2 Proteins ; Nuclear Proteins ; chemistry ; genetics ; metabolism ; Nucleotidyltransferases ; chemistry ; genetics ; metabolism ; Protein Binding ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Proteins ; chemistry ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; chemistry ; genetics

OBJECTIVETo investigate the relationship between mutations of rtM204V/I (methionine to valine or isoleucine at position rt204 of reverse transcriptase domain) in the hepatitis B virus (HBV) polymerase gene and the G1896A and G1899A single mutations in the pre-eore (PC) region and the A1762T and G1764A double-mutations in the basal core promoter (BCP) region.

METHODSA total of 2,849 hepatitis B complete genome sequences were retrieved from the GenBank/EMBL/DDBJ. The amino acid sequence of the of reverse transcriptase domain and genome sequences of the PC region and the BCP region were aligned using MEGA4 software. Data were calculated using Microsoft Excel and evaluated using SPSS 13.0 statistical software.

RESULTSAmong the 2, 849 HBV complete genome sequences, 217 (8%) strains were identified with Y(I/V) DD and 120 of those had the YIDD mutation and 97 had the YVDD mutation. Of the 1543 strains (54.2%) with PC-BCP mutations, seven mutation patterns of G 1896A-G 1899A-G 1896A-G 1899A-A 1762T/G 1764A, A 1762T/G 1764AG 1896A, A 1762T/G 1764A-G 1899A, and A 1762T/G 1764A-G 1896A-G 1899A were identified. of YMDD and PC-BCP had a higher incidence than the single YMDD mutation (76% vs 24.0%, x2=45.283, P=0.000). The double-mutations of YIDD and PC-BCP had a higher incidence than the double-mutation of YVDD and PC-BCP (85% vs 64.9%, x2=11.836, P=0.000). The double-mutation for lamivudine resistance of YMDD and PC-BCP had a higher incidence than the double pre-existent YMDD and PC-BCP mutations (89.3% vs 58.9%, x2=27.084, P=0.000). The three mutation patterns of G1896A-G1899A (P=0.000, OR=7.573), A1762T/G1764A-G1899A (P=0.000, OR=6.539) and A1762T/G1764A-G1896A-G1899A (P=0.000, OR=6.596) were associated with a greater risk of developing the YIDD mutation, according to binary logistic analysis.

CONCLUSIONThere is a relationship between the HBV YI/VDD mutation and PC-BCP mutations. Different PC-BCP mutation patterns have different effects on the YI/VDD mutation.

Base Sequence ; DNA Nucleotidyltransferases ; Genome, Viral ; Hepatitis B virus ; Lamivudine ; Mutation ; Promoter Regions, Genetic

We researched the mechanism of African swine fever virus (ASFV) protein E248R in regulating the cGAS-STING pathway. First, we verified via the dual-luciferase reporter assay system that E248R protein inhibited the secretion of IFN-β induced by cGAS-STING or HT-DNA in a dose-dependent manner. The relative quantitative PCR analysis indicated that the overexpression of E248R inhibited HT-DNA-induced transcription of <i>IFN-b1i>, <i>RANTESi>, <i>IL-6i>, and <i>TNF-αi> in PK-15 cells. Next, we found that E248R interacted with STING by co-immunoprecipitation assay and laser confocal microscopy. Finally, we demonstrated that E248R inhibited the expression of STING protein by using Western blotting. We demonstrated for the first time that the E248R protein of ASFV suppressed the host innate immune response via inhibiting STING expression. The results are pivotal in extending the understanding of the ASFV immune escape and can guide the design of vaccines against ASFV.
African Swine Fever Virus/genetics* ; Animals ; DNA ; Immunity, Innate ; Nucleotidyltransferases/metabolism* ; Signal Transduction ; Swine

Stable transformants for mammalian cells from gene transfer often show extreme variability in expression of the introduced transgene. This occurs from the highly variable number of copies integrated into the genome and from position effects on gene expression due to random integration. We constructed engineered CHO strains that can be used for high-level production of foreign proteins by gene-targeting. After transfecting dihydroforate reductase (DHFR)-deficient CHO cells with a newly screening vector plasmid pMCEscan, which carrying a FRT-neo*-IRES-k2tPA fusion gene and a DHFR gene, we screened colonies by k2tPA expression level. We selected 7 clones that expressed high level of k2tPA and carried one copy of the plasmid in their chromosomes. These clones showed in high level k2tPA production without amplification. So we targeted reporter gene (k2tPA) to test the basal expression ability of these cells clones. The clone, 8-1, showed the same effect to high base expression level. In this clone, the FRT-neo*-IRES-tPA gene was integrated at a transcription-active, DHFR-mediated, gene-amplifiable locus in the chromosomes. A gene-targeting vector, carrying a FRT-fused hygromycin-resistance gene, was constructed to target desired genes in chromosomal FRT by FLP recombinase-mediated site-specific recombination. Using this cell-vector system, we could reproducibly obtain high producers of recombinant proteins by gene-targeting and gene amplification. Using the site-specific integration CHO/dhfr- cell line 8-1, the expression level of k2tPA could amount to 17.1 microg/10(6) cell x 24 h.
Animals ; CHO Cells ; Cricetinae ; Cricetulus ; DNA Nucleotidyltransferases ; genetics ; Gene Amplification ; Gene Targeting ; methods ; Genes, Reporter ; Genetic Engineering ; methods ; Recombinant Proteins ; biosynthesis ; genetics ; Tetrahydrofolate Dehydrogenase ; genetics

Selectable marker genes that usually encode antibiotic or herbicide resistances are widely used for the selection of the transgenic plants, but they become unnecessary and undesirable after transformation selection. An important strategy to improve the transgenic plants' biosafety is to eliminate the marker genes after successful selection. In the FLP/frt site-specific system of the 2 microm plasmid of Saccharomyces cerevisiae, the FLP enzyme efficiently catalyzes recombination between two directly repeated FLP recombination target (frt) sites, eliminating the sequence between them. By controlled expression of the FLP recombinase and specific allocation of the frt sites within transgenic constructs, the system can be applied to eliminate the marker genes after selection. Through a series of procedures, the plant FLP/frt site-specific recombination system was constructed, which included the frt containing vector pCAMBIA1300-betA-frt-als-frt and the FLP expression vector pCAMBIA1300-hsp-FLP-hpt. The FLP recombinase gene was introduced into transgenic (betA-frt-als-frt) tobacco plants by re-transformation. In re-transgenic plants, after heat shock treatment, the marker gene als flanked by two identical orientation frt sites could be excised by the inducible expression of FLP recombinase under the control of hsp promoter. Excision of the als gene was found in 41% re-transgenic tobacco plants, which indicated that this systerm could make a great contribution to obtain the marker free transgenic plants.
Base Sequence ; DNA Nucleotidyltransferases ; metabolism ; Molecular Sequence Data ; Plants, Genetically Modified ; genetics ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; Recombination, Genetic ; Tobacco ; genetics

Galactosemia is a group of inherited enzyme deficiencies characterized by increase in the blood galactose levels. This condition may be associated with deficiencies of galactose-1-phosphate uridyl transferase, galactokinase, or uridine diphosphate galactose-4-epimerase. However, the elevated galactose identified by neonatal screening tests has several other possible etiologies, including hepatic hemangioendothelioma, hepatic hemangioma, and patent ductus venosus with hypoplasia of the portal vein. We report a 13-day-old Korean male with hepatic hemangioendothelioma, which was incidentally detected during the evaluation for suspected galactosemia. Laboratory studies revealed that mildly elevated levels of galactose, galactose-1-phosphate and alpha-fetoprotein, at the time of admission, were gradually decreased to the normal range over the 6 months of observation. Ultrasonography showed a well-defined heterogeneous hypoechoic mass in the liver, and magnetic resonance imaging study showed multiple enhanced mass lesions, which was compatible with the diagnosis of a hepatic hemangioendothelioma. Thus, hepatic imaging, especially ultrasonography, should be performed if neonatal screening suggests galactosemia.
alpha-Fetoproteins ; Galactokinase ; Galactose ; Galactosemias ; Galactosephosphates ; Hemangioendothelioma ; Hemangioma ; Humans ; Infant ; Infant, Newborn ; Liver ; Magnetic Resonance Imaging ; Male ; Neonatal Screening ; Portal Vein ; Reference Values ; UDPglucose-Hexose-1-Phosphate Uridylyltransferase ; Uridine Diphosphate ; Vascular Malformations

The systematic position of Fritillaria hupehensis has been in dispute. Phylogentic analyses were conducted on sequences of ITS, rpl16, matK sequences for species of F. hupehensis and allies. Lilium davidii was designed as outgroup. The analyses were performed using MP and ML methods. Conclusions could be achieved as follow. The topologies of MP and ML are consistent. The samples of F. hepehensis from different places form a supported clade with a strong bootstrap. And then form a strongly supported clade with F. anhuiensis, F. monantha. The results suggests that although F. hupehensis has a closet relation with the two ones, it exists some difference.
DNA, Plant ; chemistry ; genetics ; DNA, Ribosomal Spacer ; genetics ; Endoribonucleases ; genetics ; Fritillaria ; classification ; genetics ; Molecular Sequence Data ; Nucleotidyltransferases ; genetics ; Phylogeny ; Plant Leaves ; genetics ; Ribosomal Proteins ; genetics ; Sequence Analysis, DNA ; Species Specificity

OBJECTIVETo study the phylogeny relationship and molecular identification of 10 species from Huperzia (Huperziaceae) based on matK gene sequences data.

METHODTotal DNA of nine species from Huperzia was extracted; matK gene sequence was amplified by PCR. PCR product was directly sequenced after purification.

RESULTThe chloroplast matK gene nucleotide sequences from 9 species of Huperzia species were sequenced. The matK gene nucleotide sequences length was 1 589 bp. Analysis with Huperzia lucidula matK gene nucleotide sequences (download from GenBank) and taking Lycopodiella cernua as outgroup, Maximum Parsimony, Neighbor-Joining analyses and genetic distances were conducted using MEGA 3.1 software. 35 variable sites and 35 parsimony informative sites have been found. Pairwise genetic distances among 10 species of Huperzia was 1.59% - 0.25%.

CONCLUSIONThe results were consistent with the taxonomy in morphological of Huperzia. But H. longipetiolata and H. serrata were resolved into in different clade. There are 19 different sites of matK gene sequences between H. longipetiolata and H. serrata, the genetic distances is 0.121%. It is suggested H. longipetiolata should be as an independent species.

DNA, Chloroplast ; genetics ; DNA, Plant ; chemistry ; genetics ; Endoribonucleases ; genetics ; Huperzia ; classification ; enzymology ; genetics ; Molecular Sequence Data ; Nucleotidyltransferases ; genetics ; Phylogeny ; Plant Proteins ; genetics ; Plants, Medicinal ; classification ; enzymology ; genetics ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Species Specificity

AIMTo provide molecular evidence for quality evaluation and GAP production of Pogostemon cablin (Blanco) Benth. cultivated in different regions in Guangdong and Hainan provinces, China, by comparing two sequences (1.2 kb of plastid matK gene and 1.8 kb of nuclear 18S rRNA gene) and two chemotypes (Pogostone-type and Patchouliol-type in essential oil composition).

METHODSPCR direct sequencing was applied to detemine the matK and 18S rRNA sequences for six samples of Pogostemon cablin from different localities.

RESULTSThe matK sequences of six samples of Pogostemon cablin from different regions of cultivation are 1,245 bp in length, which coding 415 amino acids of protein (maturase), and 18S rRNA sequences are 1,803-1,805 bp in size. Based on multiple sequence alignment, there are 47 variable sites in the matK sequence of these six samples, 17 in the 18S rRNA sequence. The cluster tree reconstructed by UPGMA method shows that the sequence divergence both in matK and 18S rRNA genes among six samples of Pogostemon cablin was well correlative with their regions of cultivation and intraspecific chemotypes of essential oil composition.

CONCLUSIONCombining with chemical and biogeographical data, DNA sequencing can become a powerful tool in the key technique-species identification of quality evaluation and GAP production of Pogostemon cablin.

Base Sequence ; DNA, Plant ; analysis ; Endoribonucleases ; genetics ; Genes, Plant ; Lamiaceae ; chemistry ; classification ; genetics ; Molecular Sequence Data ; Nucleotidyltransferases ; genetics ; Oils, Volatile ; analysis ; Polymorphism, Genetic ; Quality Control ; Sequence Analysis, DNA ; Species Specificity

AIMTo provide more molecular evidences for species relationship between Chuanxiong (Ligusticum chuanxiong Hort.) from China and Japanese Chuanxiong (Senkyu in Japanese) (Cnidium officinale Makino).

METHODSTo sequence such two genes as internal transcribed spacer (ITS) from nuclear rDNA and maturase for lysine (matK) in tRNA(lys) (UUU) intron from chloroplast DNA of both Ligusticum chuanxiong and Cnidium officinale using PCR direct sequencing and to analyze the sequence variation of two genes between these two species.

RESULTSThe matK gene sequence of Ligusticum chuanxiong and Cnidium officinale is 1268 bp in length, coding 422 amino acids of maturase protein. ITS gene sequence 699 bp, consisting of 54 bp of 18S rRNA-3', 215 bp of ITS1, 162 bp of 5.8S rRNA, 222 bp of ITS2, 46 bp of 26S rRNA-5'. Multiple sequence alignment shows that the sequence of two genes between dried crude drug and fresh voucher material of Ligusticum chuanxiong and Cnidium officinale, there is 1 variable site (T-->C) in matK (upstream at 595 nt) and ITS (ITS1 at 54 nt) between Ligusticum chuanxiong and Cnidium officinale.

CONCLUSIONBased on homology analysis of two genes plastid matK and nuclear ITS, the origin of Chuanxiong from China and Japan ought to be identical, the scientific name Cnidium officinale of Japanese Chuanxiong should be changed to Ligusticum chuanxiong.

Amino Acid Sequence ; Base Sequence ; China ; Cnidium ; genetics ; DNA, Plant ; analysis ; DNA, Ribosomal Spacer ; genetics ; Endoribonucleases ; genetics ; Japan ; Ligusticum ; genetics ; Molecular Sequence Data ; Nucleotidyltransferases ; genetics ; Phylogeny ; RNA, Ribosomal, 18S ; genetics ; Sequence Analysis ; Sequence Homology ; Terminology as Topic