Chromagenics B.v.

Cellagenics B.v.

Arie Pieter Otte

Arthur Leo Kruckeberg

Henricus Johannes Maria Van Blokland

Richard George Antonius Bernardus Sewalt

John Antonius Verhees

Theodorus Hendrikus Jacobus Kwaks

Theodorus H J Kwaks

Henricus J M Van Blokland

Richard G A B Sewalt

Femke Hoeksema

David P E Satijn

Michel Siep

Henricus Jm Van Blokland

Arhur Leo Kruckeberg

The present invention relates to nucleic acid fragments and constructs comprising genomic nucleotide sequences, which are present upstream of Rb1 and p15C that are associated with intergenic transcription, for the production of a gene product of interest in a eukaryotic, preferably mammalian, host cell in the presence of a stringent selectable marker. The invention further relates to host cells comprising the nucleic acid constructs, to methods for generating the host cells and to methods for producing a gene product of interest using the host cells.

Intergenic elements for enhancing gene expression

The present invention relates to nucleic acid constructs comprising selectable marker genes in a multicistronic transcription unit for use in the generation and selection of eukaryotic host cells for expression of a gene product of interest. For increased stringency of selection, the coding sequence of the selectable marker may be directed preceded by a relatively short functional open reading frame to reduce the efficiency of translation of the selectable marker, and/or the amino acid sequence of the selectable marker may comprise one or more mutations that reduce the level of resistance provide by the mutated marker as compared to its wild type counterpart. The invention further relates to methods for generating eukaryotic host cells for expression of a gene product of interest, wherein these nucleic acid constructs are used, and to methods for producing a gene product of interest wherein thus generated host cells are applied.

Stringent selectable markers

The present invention relates to nucleic acid fragments and constructs comprising genomic nucleotide sequences from the promoter region of a 60S ribosomal protein L32 gene (RPL32), for the production of a gene product of interest in a eukaryotic, preferably mammalian, host cell in the presence of a stringent selectable marker. The invention further relates to host cells comprising the nucleic acid constructs, to methods for generating the host cells and to methods for producing a gene product of interest using the host cells.

Nucleic acid fragments from a ribosomal protein promoter for enhancing gene expression

Described is a DNA molecule comprising an open reading frame sequence encoding a selectable marker polypeptide, wherein the DNA molecule in the coding strand comprises a translation start sequence for the selectable marker polypeptide having a GTG or TTG start codon, and wherein the ORF sequence that encodes the selectable marker protein has been mutated to replace at least half of its CpG dinucleotides as compared to the native ORF sequence that encodes the selectable marker protein. Further provided are such DNA molecules wherein the ORF sequence that encodes a selectable marker polypeptide is part of a multicistronic transcription unit that further comprises an open reading frame sequence encoding a polypeptide of interest. Also described are methods for obtaining host cells expressing a polypeptide of interest, wherein the host cells comprise the DNA molecules described herein. Further provided is the production of polypeptides of interest, comprising culturing host cells comprising the DNA molecules described herein.

Selection of host cells expressing protein at high levels

The invention provides a DNA molecule comprising a multicistronic transcription unit coding for i) a polypeptide of interest, and for ii) a selectable marker polypeptide functional in a eukaryotic host cell, wherein the polypeptide of interest has a translation initiation sequence separate from that of the selectable marker polypeptide, and wherein the coding sequence for the polypeptide of interest is upstream from the coding sequence for the selectable marker polypeptide in the multicistronic transcription unit, and wherein an internal ribosome entry site is present downstream from the coding sequence for the polypeptide of interest and upstream from the coding sequence for the selectable marker polypeptide, and wherein the nucleic acid sequence coding for the selectable marker polypeptide in the coding strand comprises a GTG or a TTG start codon. Also provided are methods for obtaining host cells expressing a polypeptide of interest, such host cells comprising DNA molecules of the invention. Further provided is the production of polypeptides of interest, comprising culturing host cells comprising the DNA molecules of the invention.

The invention provides a DNA molecule comprising a multicistronic transcription unit coding for i) a selectable marker polypeptide functional in a eukaryotic host cell, and for ii) a polypeptide of interest, the polypeptide of interest having a translation initiation sequence separate from that of the selectable marker polypeptide, characterized in that the coding sequence for the polypeptide of interest is downstream from the coding sequence for the selectable marker in the multicistronic transcription unit, and the nucleic acid sequence coding for the selectable marker polypeptide comprises a mutation that decreases the translation efficiency of the selectable marker in a eukaryotic host cell. The invention also provides methods for obtaining host cells expressing a polypeptide of interest, the host cells comprising the DNA molecules of the invention. The invention further provides the production of polypeptides of interest, comprising culturing host cells comprising the DNA molecules according to the invention.

Described are means and methods for providing a cell with a protein expression unit, the method comprising providing a nucleic acid sequence comprising the unit with a nucleic acid sequence encoding a binding site for a member of a chromatin modification system for rendering chromatin more accessible for transcription (opener), wherein the opener is present in the cell. Preferred openers comprise histone modification proteins, chromatin remodeling proteins and trithorax group proteins or equivalents. The cells thus generated and nucleic acid sequences encoding such openers are provided. Openers are preferred in the context of STAR and TRAP sequences.

Means and methods for producing a protein through chromatin openers that are capable of rendering chromatin more accessible to transcription factors

The present invention relates to the production of proteins in a cell or host cell. The invention uses a TRAnscription Pause (TRAP) sequence to enhance a protein expression characteristic of a protein expression unit. The TRAP sequence is thought to prevent, at least in part, formation of antisense RNA or to, at least in part, prevent transcription to enter the protein expression unit. In one embodiment, the invention provides a method for expression of at least one protein of interest in a cell comprising providing the cell with at least one protein expression unit that comprises a promoter functionally linked to an open reading frame encoding at least one protein of interest, characterized in that the protein expression unit further comprises at least one TRAP sequence and wherein the TRAP sequence is functionally located downstream of the open reading frame and at least in part prevents formation of antisense RNA. In another embodiment, the TRAP sequence is functionally located upstream of the promoter and at least in part prevents transcription to enter the expression unit. Preferably, the expression protein unit further comprises at least one STabilizing Anti-Repressor sequence.

Method for improving protein production

The invention provides a DNA molecule comprising an open reading frame sequence that encodes a selectable marker polypeptide, wherein said DNA molecule in the coding strand comprises a translation start sequence for the selectable marker polypeptide having a GTG startcodon or a TTG startcodon, and wherein the open reading frame sequence that encodes the selectable marker protein has been mutated to replace at least half of its CpG dinucleotides as compared to the native open reading frame sequence that encodes the selectable marker protein.

The invention provides recombinant DNA molecules comprising novel expression augmenting DNA fragments and an expression cassette, said expression cassette comprising a heterologous promoter linked to a nucleic acid of interest. The invention further provides uses of the novel expression augmenting DNA fragments. The invention further provides methods for obtaining novel expression augmenting DNA fragments.

Expression augmenting DNA fragments, use thereof, and methods for finding thereof

Described is the production of proteins in a host cell. Even more specifically, described are methods for improving expression of two or more proteins in a cells or host cell. The methods are suited for production of, for example, recombinant antibodies that can be used in pharmaceutical preparations or as diagnostic tools. In certain embodiments, provided are methods for obtaining a cell that expresses two or more proteins comprising providing the cell with two or more protein expression units encoding two or more proteins, characterized in that at least two of the protein expression units comprise at least one STAR sequence.

Method for simultaneous production of multiple proteins; vectors and cells for use therein

Described is the production of proteins in a host cell. More specifically, described are methods for improving expression of two or more proteins in a cell or host cell. The methods are suited for production of, for example, recombinant antibodies that can be used in pharmaceutical preparations or as diagnostic tools. In one embodiment, provided is a method for obtaining a cell that expresses two or more proteins comprising providing the cell with two or more protein expression units encoding two or more proteins, characterized in that at least two of the protein expression units comprise at least one STAR sequence.

The invention provides a novel anti-repressor element, which is useful for improving expression of nucleic acid in host cells. Methods using the novel anti-repressor element for producing a protein of interest are also provided. The invention also provides new configurations of expression cassettes comprising anti-repressor elements.

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Amersfoort, Netherlands

Arie Pieter Otte