Regeneron Pharmaceuticals, Inc.

David Heslin

Lynn Macdonald

David M Valenzuela

David Frendewey

Ka-Man Venus Lai

Wojtek Auerbach

Jeffrey D Lee

Alexander O Mujica

Gustavo Droguett

Chia-Jen Siao

Chunguang Guo

Daisuke Kajimura

Aarti Sharma-Kanning

Roxanne Ally

Jeffrey Lee

Michael Lacroix-Fralish

Compositions and methods are provided for making rat pluripotent and totipotent cells, including rat embryonic stem (ES) cells. Compositions and methods for improving efficiency or frequency of germline transmission of genetic modifications in rats are provided. Such methods and compositions comprise an in vitro culture comprising a feeder cell layer and a population of rat ES cells or a rat ES cell line, wherein the in vitro culture conditions maintain pluripotency of the ES cell and comprises a media having mouse leukemia inhibitory factor (LIF) or an active variant or fragment thereof. Various methods of establishing such rat ES cell lines are further provided. Methods of selecting genetically modified rat ES cells are also provided, along with various methods to generate a transgenic rat from the genetically modified rat ES cells provided herein. Various kits and articles of manufacture are further provided.

Genetic modification of rats

A non-human animal (e.g., a rodent) model for diseases associated with a C9ORF72 heterologous hexanucleotide repeat expansion sequence is provided, which non-human animal comprises a heterologous hexanucleotide repeat (GGGGCC) in an endogenous C9ORF72 locus. A non-human animal disclosed herein comprising a heterologous hexanucleotide repeat expansion sequence comprising at least one instance, e.g., repeat, of a hexanucleotide (GGGGCC) sequence may further exhibit a characteristic and/or phenotype associated with one or more neurodegenerative disorders (e.g., amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD), etc.). Methods of identifying therapeutic candidates that may be used to prevent, delay or treat one or more neurodegenerative (e.g., amyotrophic lateral sclerosis (ALS, also referred to as Lou Gehrig's disease) and frontotemporal dementia (FTD)) are also provided.

Non-human animals having a hexanucleotide repeat expansion in a C9ORF72 locus

Targeting constructs and methods of using them are provided for differentiation-dependent modification of nucleic acid sequences in cells and in non-human animals. Targeting constructs comprising a promoter operably linked to a recombinase are provided, wherein the promoter drives transcription of the recombinase in an differentiated cell but not an undifferentiated cell. Promoters include Blimp1, Prm1, Gata6, Gata4, Igf2, Lhx2, Lhx5, and Pax3. Targeting constructs with a cassette flanked on both sides by recombinase sites can be removed using a recombinase gene operably linked to a 3'-UTR that comprises a recognition site for an miRNA that is transcribed in undifferentiated cells but not in differentiated cells. The constructs may be included in targeting vectors, and can be used to automatically modify or excise a selection cassette from an ES cell, a non-human embryo, or a non-human animal.

miRNA-regulated differentiation-dependent self-deleting cassette

MiRNA-regulated differentiation-dependent self-deleting cassette

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Closter, NJ, United States of America

David Heslin