The invention relates to the control of gene expression. Specifically, the invention provides compositions and methods for the production and use of recombinant nucleic acid molecules that have the ability to specifically downregulate an expressed target gene in vivo. In some aspects, the invention provides methods for producing a hairpin DNA molecule where part of the molecule is derived from an mRNA that is a target for a small interfering RNA (siRNA) derived from the hairpin. In other aspects, the invention provides synthetic hairpin adapter oligonucleotides that are used in the construction of siRNA-producing cassettes. In other aspects, the invention provides methods for testing for the presence or absence of specific inhibitory activity of an RNAi trigger molecule, and in still other aspects, the invention provides methods for identifying an active RNAi trigger molecule from a library of RNAi trigger molecules. In still other aspects, the invention provides methods for identifying a polynucleotide from a plurality of candidate target polynucleotides that is specifically targeted by an RNAi trigger molecule. In other aspects, the invention provides epi-allelic series of hypomorphic RNAi trigger molecules specific for any gene of interest, where the series of RNAi trigger molecules have a variety of uses including analysis of gene function and drug target development.

A method of detecting and quantifying various enzymatic activities using a constructed artificial genetic circuit GESS (genetic enzyme screening system) for sensing phenolic compounds and a method of screening a trace of activities of target enzymes from a metagenome using the artificial genetic circuit, thereby securing target enzyme genes. When the method for screening and quantifying target enzymatic activity is used, useful genes can be screened from various genetic communities, including environmental or metagenomic libraries, at a single cell level in high throughput (million/day). Further, the sensitivity of the genetic circuit to phenol derivatives and the expression thereof can be controlled, and thus the genetic circuit can rapidly sense and quantify various enzymatic activities. Thus, the method can be advantageously used in the protein engineering technology for enzyme modification. Particularly, it can quantitatively investigate enzymatic activity, and thus can be applied to molecular evolution technology.

Disclosed is a mouse artificial chromosome vector, comprising: a natural centromere derived from a mouse chromosome; a mouse-chromosome-derived long-arm fragment formed by deleting a long-arm distal region at a mouse chromosome long-arm site proximal to the centromere; and a telomere sequence, wherein the vector is stably retained in a cell and/or tissue of a mammal. In addition, disclosed are cells or non-human animals comprising the vector, and use of the cells or non-human animals.

Provided are mutant viral capsid cell libraries, individual cells of such libraries, systems, vectors, and methods for generating the cell libraries, and methods of use thereof to screen for mutant viral capsids with desired characteristics.

Disclosed herein are compositions, methods, and systems for selecting a polynucleotide for activity as a neuronal-specific transcription factor. The system may include a polynucleotide encoding a reporter protein and a pan-neuronal marker, a Gas protein, and a library of guide RNAs (gRNAs) targeting putative transcription factors. Further provided are methods of screening for a neuronal-specific transcription factor.

A generally applicable method for the selective covalent attachment of a reporter molecule to a replicating entity that allows one to obtain specific binders from a single round of library screening is disclosed. For example, selective biotinylation of phage particles and yeast cells displaying a binder to any given target can be achieved via application of a coupled enzyme reaction that includes a peroxidase, an oxidase and a catalase.

This document relates to materials and methods for the production of protein. In one aspect, this document provides a nucleic acid construct including a first alcohol oxidase promoter element, wherein the first alcohol oxidase promoter element includes a mutation at one or more nucleotide positions corresponding to any of nucleotide positions 668-734 relative to SEQ ID NO: 28.

The present invention relates to methods associated with metagenomic screening for metabolite induced elements (MIEs) and the subsequent use of the MIEs in screening metagenomic libraries to identify metabolic pathways and pathway components in one or more partial or complete operons. In one aspect the method may be an iterative approach to metagenomic screening which involves substrate and product selection.

Methods of constructing a cell comprising in its chromosome one or more copies of an open reading frame (ORF) or operon encoding at least one polypeptide of interest, each copy being under the transcriptional control of a heterologous promoter using a site specific recombinase and in vivo integration by recombination; resulting cells, and methods for producing a polypeptide of interest using the resulting cells.

An expression vector, comprising a first reporter nucleic acid sequence operably linked to a first expression control sequence comprising a promoter; and a second reporter nucleic acid sequence operably linked to a second expression control sequence that comprises a response element that is activated or inactivated as one or more of the cells differentiate or dedifferentiate. Methods and kits for imaging and monitoring stem cells comprising the expression vector are also provided.