The present invention refers to a fusion protein or a protein complex comprising a DNA binding protein (DnaBP), a nucleobase modifying protein (NMP), and a Base Excision Repair associated protein (BERAP. Also, described herein are a method of replacing a cytosine with a guanine on a DNA strand in a cell and a method of treating a subject having or suspected of having a disease or disorder.

Disclosed are compositions and methods for gene editing. The present disclosure relates to compositions and methods for gene editing using a Cas nickase to cleave a double-stranded nucleic acid sequence near a target site and a ligase to incorporate a nucleic acid into a double-stranded nucleic acid sequence. The present disclosure also provides reagents for use in the gene editing methods. The present disclosure further provides kits containing reagents for use in the gene editing methods.

The present invention relates, e.g., to in vitro method, using isolated protein reagents, for joining two double stranded (ds) DNA molecules of interest, wherein the distal region of the first DNA molecule and the proximal region of the second DNA molecule share a region of sequence identity, comprising contacting the two DNA molecules in a reaction mixture with (a) a non-processive 5′ exonuclease; (b) a single stranded DNA binding protein (SSB) which accelerates nucleic acid annealing; (c) a non strand-displacing DNA polymerase; and (d) a ligase, under conditions effective to join the two DNA molecules to form an intact double stranded DNA molecule, in which a single copy of the region of sequence identity is retained. The method allows the joining of a number of DNA fragments, in a predetermined order and orientation, without the use of restriction enzymes.

Provided are a method for large-scale synthesis of a long-chain RNA and a method for site-specific modification of the long-chain RNA. The method for large-scale synthesis of a long-chain RNA comprises: designing short RNA fragments and splint DNA fragments; ligating; capping; and removing the splint DNA fragments and other steps. A large number of short RNA fragments and different splint DNA fragments are chemically synthesized, and then the different short RNA fragments are ligated by a biological method so as to form a target long-chain RNA. The product long-chain RNA has a low mutation rate, a plurality of the short RNA fragments can be assembled in a single reaction, and the long-chain RNA can be synthesized at a high throughput so as to fulfill the large-scale production of the long-chain RNA. In addition, by chemical modification of the short RNA fragments, the site-specific modification of the long-chain RNA can be realized.

The present invention relates to the field of ligases. More specifically it relates to novel and highly efficient ATP-dependent DNA ligases with a unique ligase activity making the ligase particularly useful in a variety of molecular biology techniques. Furthermore, the invention relates to compositions and kits comprising the DNA ligase, methods for its manufacture and use.

Disclosed is a preparation method for a DNA next-generation sequencing library, including steps: digestion, end repair, and A-tailing of genomic DNA; adapter ligation of DNA fragments; bead purification of product after adapter ligation; PCR amplification of DNA fragments; and selection and purification of PCR product fragments. The preparation method for the DNA next-generation sequencing library includes steps: fractionating by VVN and T7 through a single-step reaction process with double digestion and end repair, blunting a 5′-overhang under the polymerization action of a Taq DNA polymerase, adding an A (adenine) to a 3′-end, and achieving the preparation of the DNA next-generation sequencing library under an integrated single-step reaction. After the single-step reaction ends, bead purification isn't required, so that the preparation process is simple. In the preparation process, there is no preference for two restriction enzymes, which achieves the sequencing of target fragments.

Methods, assays, compositions and kits for the ligation of short polynucleotides are presented herein. The short polynucleotides are optionally no more than 7 nucleotides in length, and can be as short as 3 or 4 nucleotides in length. The ligation is optionally performed by CV ligase.

A number of T4 DNA ligase mutants exhibiting enhanced ligation activity in the presence of high salt concentrations compared to the wild-type ligase were engineered, characterized, and selected via gel electrophoresis of ligation products from a standard ligation assay. Ligase catalyzes the formation of phosphodiester bonds between the 5′ and 3′ ends of complementary cohesive ends or blunt ends of duplex DNA, a process that is vital to numerous molecular biology processes including cloning and sequencing.

Modified nucleotides, and methods to modify nucleotides with a moiety or label, such as biotin, that permits their detection and results in a modified nucleotide, and methods of use of the modified nucleotide in quantitative and qualitative assays.

Provided herein are compositions, systems, and methods using multiple ligases, wherein at least one of the ligases is an adenylation-deficient ATP-dependent ligase or an un-adenylated ATP-dependent ligase (e.g., present in an ATP free mixture). In certain embodiments, multiple ligases are used to ligate a pre-adenylated double stranded sequence to a non-adenylated double stranded sequence (e.g., the adenylation-deficient ATP-dependent ligase or un-adenylated ATP-dependent ligase ligates the first strand, and a second ligase ligates the second strand). In other embodiments, provided herein are mutant T4 ligases (e.g., K159S mutant or K159C mutant).