Ftsj1 Knockout HT22 Cell Line

The Ftsj1 Knockout HT22 Cell Line is a CRISPR/Cas9-edited knockout cell line originating from the HT22 immortalized mouse hippocampal neuronal cell line. This product carries a targeted disruption of the Ftsj1 gene, which encodes the RNA 2′-O-methyltransferase FTSJ1. By eliminating functional FTSJ1 protein, this model enables detailed investigation of RNA modification-dependent processes in a neuronal background.

HT22 cells were originally established from postnatal mouse hippocampal HT4 cells and have become a widely adopted model for studying oxidative stress and neurotoxicity. Unlike primary neurons, these immortalized cells lack functional ionotropic glutamate receptors; however, they undergo oxidative cell death when exposed to high concentrations of extracellular glutamate via a pathway involving inhibition of the cystine/glutamate antiporter, leading to glutathione depletion and accumulation of reactive oxygen species. This unique property makes HT22 cells particularly valuable for examining neuronal vulnerability independent of excitotoxicity.

The FTSJ1 protein belongs to the SPOUT methyltransferase family and specifically catalyzes the 2′-O-methylation of cytidine residues within tRNA and rRNA molecules. Its well-characterized substrates include cytidine 32 (C32) of tRNA(Phe) and cytidine 4447 (C4447) of 28S rRNA, with the methylation reaction dependent on the cofactor S-adenosyl-L-methionine. These modifications are critical for maintaining tRNA stability, proper ribosomal assembly, and translational fidelity. FTSJ1 functions within a network of RNA-modifying enzymes, and its activity is essential for the precise control of protein synthesis. Although the upstream transcriptional regulation of Ftsj1 remains largely undefined, its downstream effects converge on the translational machinery, impacting ribosome biogenesis and global translation rates.

In the context of HT22 hippocampal neurons, loss of Ftsj1-mediated RNA methylation provides a direct link to neurodevelopmental disorders. Mutations in FTSJ1 are causally associated with X-linked intellectual disability and non-syndromic mental retardation, likely due to impaired translation of synaptic proteins and neuronal dysfunction. This knockout cell line, combined with the HT22 model’s inherent sensitivity to oxidative stress, allows researchers to dissect how disrupted translation fidelity may exacerbate oxidative damage pathways. It offers a tractable system to explore the molecular basis of cognitive impairment, including studies on ribosome heterogeneity and stress-induced translational reprogramming in neurons.

Experimental applications of the Ftsj1 Knockout HT22 Cell Line encompass a broad range of molecular and cellular techniques. Loss of FTSJ1 protein can be verified by Western blotting, while RT-qPCR can monitor expression of downstream RNA targets. RNA modification status can be assessed using primer extension assays or high-throughput methods such as RiboMeth-seq, and polysome profiling enables evaluation of translation efficiency. Functional assays may include glutamate toxicity tests to measure oxidative stress responses, MTT viability assays, and immunofluorescence for neuronal markers. Transcriptome-wide analyses via RNA-seq can identify gene expression changes resulting from impaired RNA methylation. This cell line is a rigorous tool for investigating the roles of tRNA and rRNA modifications in neuronal health and disease. For additional information, please contact Ascent Research.