Novel eukaryotic cells and methods for recombinantly expressing a product of interest

Abstract

The disclosure pertains to novel eukaryotic cell suitable for recombinant production of a product of interest, wherein the genome of the host cell is altered so that the effect of protein FAM60A is impaired in said cell, e.g. by reducing or eliminating functional expression of gene FAM60A thereby improving the stability characteristics. Furthermore, the present disclosure provides associated technologies wherein such host cells are used in recombinant production technologies.

1 . A method comprising analysing eukaryotic cells for their suitability as host cells for recombinant expression of a product of interest by analyzing directly or indirectly whether the effect of FAM60A is impaired in said cells. 
     
     
         2 . The method according to  claim 1 , wherein the directly analyzing comprises analyzing whether the functional expression of gene FAM60A is reduced or eliminated in said cells. 
     
     
         3 . The method according to  claim 1 , wherein the FAM60A protein shares at least 75% identity to one or more of the amino acid sequences shown in SEQ ID NO: 1 to 8. 
     
     
         4 . The method according to  claim 1 , wherein the method further comprises selecting at least one cell wherein the functional expression of FAM60A is impaired because functional expression of gene FAM60A is reduced or eliminated by gene knock-out, gene mutation, gene deletion, gene silencing or a combination of any the foregoing, for recombinant expression of the product of interest. 
     
     
         5 . The method according to  claim 1 , wherein prior to analysis, the eukaryotic cells are treated with an agent that induces chromosome breakage and wherein the analysis comprises analyzing whether treatment with said agent resulted in a deletion of a portion of a chromosome which includes gene FAM60A. 
     
     
         6 . The method according to  claim 1 , wherein prior to analysis, the eukaryotic cells are transfected with a heterologous polynucleotide encoding a product of interest and a heterologous polynucleotide encoding a selectable marker, and wherein prior to analysis at least one selection step is performed to identify successfully transfected host cells. 
     
     
         7 . The method according to  claim 1 , wherein the method comprises additionally analyzing directly or indirectly whether the effect of the expression product of endogenous gene C12orf35 is impaired in said cells, wherein the C12orf35 gene is a gene encoding a protein that shares at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity to one or more of the amino acid sequences shown in SEQ ID NO: 10 to 16 or the protein encoded by SEQ ID NO: 17. 
     
     
         8 . The method according to  claim 1 , wherein the cells are hamster cells and the method comprises analyzing whether expression of one or more genes located in the telomeric region of chromosome 8 and being selected from the group consisting of the Tmtc1 gene and genes located telomeric of the Tmtc1 gene is eliminated or reduced thereby analyzing whether the functional expression of gene FAM60A is reduced or eliminated in said cells. 
     
     
         9 . The method according to  claim 1 , wherein a plurality of cell clones is analyzed for discriminating between stable and unstable cell clones and wherein one or more cell clones wherein the functional expression of gene FAM60A is reduced or eliminated are selected as production clone. 
     
     
         10 . The method according to  claim 1 , wherein a plurality of cell clones is analyzed for discriminating between stable and unstable and between high and low producing cell clones and wherein one or more cell clones wherein the functional expression of gene FAM60A is reduced or eliminated are selected as production clone.