Tia1 Knockout mouse models

Stress granule nucleation depends on Tia1, the mouse ortholog of human TIA1, encoding a nucleocytoplasmic RNA binding protein with three RRM domains and a C-terminal prion-like low complexity domain that drives liquid-liquid phase separation. TIA1 binds U-rich sequences to promote alternative splicing and, upon eIF2alpha phosphorylation during integrated stress response activation, recruits stalled preinitiation complexes into cytoplasmic stress granules while repressing translation of specific transcripts. Missense mutations within the low complexity domain, notably P362L and E384K, alter granule dynamics and delay disassembly, causing Welander distal myopathy and contributing to ALS and frontotemporal dementia with TDP-43 pathology. Allele logic follows: patient missense knockins at the endogenous locus model altered phase behavior, whereas conditional null tests granule-independent splicing roles. Tia1 nulls show partial embryonic lethality with viable survivors, and the paralog Tial1 provides genuine functional overlap, so compound alleles are advisable when granule assembly itself is the endpoint.

Global Tia1 deletion answers broad mechanism questions quickly. If timing or site matters, conditional alleles are a natural next step after the null is characterized.