ABSTRACT
BACKGROUND NME23/NDPKs are well conserved proteins found in all living organisms. In addition to being nucleoside diphosphate kinases (NDPK), they are multifunctional enzymes involved in different processes such as DNA stability, gene regulation and DNA repair among others. TcNDPK1 is the canonical NDPK isoform present in Trypanosoma cruzi, which has nuclease activity and DNA-binding properties in vitro. OBJECTIVES In the present study we explored the role of TcNDPK1 in DNA damage responses. METHODS TcNDPK1 was expressed in mutant bacteria and yeasts and over-expressed in epimastigotes. Mutation frequencies, tolerance to genotoxic agents and activity of DNA repair enzymes were evaluated. FINDINGS Bacteria decreased about 15-folds the spontaneous mutation rate and yeasts were more resistant to hydrogen peroxide and to UV radiation than controls. Parasites overexpressing TcNDPK1 were able to withstand genotoxic stresses caused by hydrogen peroxide, phleomycin and hidroxyurea. They also presented less genomic damage and augmented levels of poly(ADP)ribose and poly(ADP)ribose polymerase, an enzyme involved in DNA repair. MAIN CONCLUSION These results strongly suggest a novel function for TcNDPK1; its involvement in the maintenance of parasite's genome integrity.
Subject(s)
Trypanosoma cruzi/enzymology , DNA Damage , Nucleoside-Diphosphate Kinase/metabolism , Trypanosoma cruzi/genetics , Poly(ADP-ribose) Polymerases , Nucleoside-Diphosphate Kinase/genetics , DNA RepairABSTRACT
Abstract Chloroplast development and chlorophyll (Chl) biosynthesis in plants are regulated by many genes, but the underlying molecular mechanisms remain largely elusive. We isolated a rice mutant named yss2 (young seedling stripe2) with a striated seedling phenotype beginning from leaf 2 of delayed plant growth. The mutant developed normal green leaves from leaf 5, but reduced tillering and chlorotic leaves and panicles appeared later. Chlorotic yss2 seedlings have decreased pigment contents and impaired chloroplast development. Genetic analysis showed that the mutant phenotype was due to a single recessive gene. Positional cloning and sequence analysis identified a single nucleotide substitution in YSS2 gene causing an amino acid change from Gly to Asp. The YSS2 allele encodes a NDPK2 (nucleoside diphosphate kinase 2) protein showing high similarity to other types of NDPKs. Real-time RT-PCR analysis demonstrated that YSS2 transcripts accumulated highly in L4 sections at the early leaf development stage. Expression levels of genes associated with Chl biosynthesis and photosynthesis in yss2 were mostly decreased, but genes involved in chloroplast biogenesis were up-regulated compared to the wild type. The YSS2 protein was associated with punctate structures in the chloroplasts of rice protoplasts. Our overall data suggest that YSS2 has important roles in chloroplast biogenesis.
ABSTRACT
Objective:To develop a method for the detection of 10 single nucleotide polymorphisms(SNPs) of Nm23 gene,and to explore the genotypic and allelic distributions of the 10 SNPs in Chinese Hans population in Wuhan.Methods: Two hundreds healthy subjects ,115 men and 85 women included ,were enrolled as DNA sample donors.The real time TaqMan-MGB genotyping assay was used for the determination of the 10 SNPs selected ,and the results were validated by direct gene sequencing.Results:The method established could accurately and quickly screen the genotypes of the 10 SNPs of Nm23/NDPK gene.Distribution frequencies of the 10 SNPs were similar to these in other researches as well as these of HCB.All the loci follow the Hardy-Weinberg equilibrium.Highly linkage disequilibriums were found between rs 16949649 and rs7207370 , rs16949649 and rs34214448 , rs2159359 and rs2302254 , rs2159359 and rs8075231 ,rs2159359 and rs2041296 ,as well as rs2159359 and rs8071647 ,respectively.Four Tag SNPs:rs34214448 , rs2302254 ,rs11868380 and rs2318785 were initially selected by Heploview software.Conclusion:The method established for SNP gen-otyping can meet the needs for rapid analysis of Nm 23 gene polymorphisms ,and may have great values in investigating the association between gene polymorphisms and diseases as well as adverse drug reactions.
ABSTRACT
NM23A protein is a kind of multifunctional protein distributed widely in the nature and it exists in almost all the or-ganism and cells. Apart from owning the nucleoside diphosphate kinase activity, NM23A also participates in the physiological process of signal transduction, gene regulation, cell growth and development and so on. NM23A plays important roles in the pa-thology process of the tumor development and metastasis and cen-tral nerve system disease.
ABSTRACT
Objective To explore the expression and significance of DPC 4/Smad 4 and nm23-H1/NDPK in human pancreatic carcinoma. Methods The expressions of DPC 4/Smad 4 and nm23/NDPK were detected by immunohistochemical method in 34 pancreatic carcinoma tissues and 34 chronic pancreatitis tissues. Results The positive rate of DPC 4/Smad 4 expression was significantly higher in the chronic pancreatitis than in the pancreatic carcinoma(P