objective(s): although viral vectors are considered efficient gene transfer agents, their board application has been limited by toxicity, immunogenicity, mutagenicity and small gene carrying capacity. non-viral vectors are safe but they suffer from low transfection efficiency. in the present study, polyallylamine (paa) in two molecular weights (15 and 65 kda) was modified by alkane derivatives ...

Bacterial restriction-modification systems provide defense against foreign DNA by using a self versus nonself recognition mechanism. A great diversity of recognition motifs is maintained in natural populations. Circumstantial evidence suggests that defense against bacteriophage viruses favors this diversity. (1) Bacterial restriction enzymes can destroy invading phage DNA. (2) Phage DNA can mim...

Modifications of the canonical structures of DNA and RNA play critical roles in cell physiology, DNA replication, transcription and translation in all organisms. We now report that bacterial dnd gene clusters incorporate sulfur into the DNA backbone as a sequence-selective, stereospecific phosphorothioate modification. To our knowledge, unlike any other DNA or RNA modification systems, DNA phos...

DNA phosphorothioate (PT) modification is a recently identified epigenetic modification that occurs in the sugar-phosphate backbone of prokaryotic DNA. Previous studies have demonstrated that DNA PT modification is governed by the five DndABCDE proteins in a sequence-selective and RP stereo-specific manner. Bacteria may have acquired this physiological modification along with dndFGH as a restri...

DNA molecules are polymers composed of basic repeating subunits of deoxyribonucleotides, which consist of the deoxyribose sugar, phosphate groups, and a nitrogenous base. They appear to fulfill all requirements necessary to maintain the genetic function of DNA. The five elements of nitrogen, phosphorus, carbon, hydrogen, and oxygen had been regarded as the canonical composition of DNA until the...

A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six Helicobacter pylori strains. Among these 18 specificities are three completely new endonucleases, Hpy178III, Hpy99I, and Hpy188I, that specifically cleave DNA at TCNNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or f...

Background: Promoter hyper-methylation of tumor suppressor genes is a common event that occurs in cancer. As methylation is a reversible modification, agents capable of reversing an abnormal methylation status should help to combat cancer. 5-Aza-CdR is a DNA methyl-transferase inhibitor. The present study aimed to evaluate the effect of 5-Aza-CdR on the proliferation of human pancreatic cancer ...

Protein arginine methylation is a widespread post-translational modification (PTM) in eukaryotic cells. This chemical proteins functionally modulates diverse cellular processes from signal transduction, gene expression, DNA damage repair,...