Trimethylguanosine synthase 1 (TGS1)

Trimethylguanosine synthase 1 (TGS1) is a highly conserved, nuclear and cytosolic **methyltransferase enzyme** responsible for the hypermethylation of snRNA and snoRNA 7-methylguanosine caps to generate 2,2,7-trimethylguanosine caps[4][1][6]. This modification plays a critical role in pre-mRNA splicing, ribosome biogenesis, and proper RNA processing, with significant effects on cellular homeostasis and stress responses[1][2]. TGS1 is essential for viability in many organisms and has been implicated in human diseases including type 2 diabetes (by regulating β-cell mass and function), certain genetic disorders, and potentially cancer, where its modulation can alter translational control[1][4][3][5]. Although no drugs currently target TGS1 clinically, it is under investigation as a **therapeutic target** for diabetes and cancer due to its pivotal roles in RNA biology and cell survival[1][5].

Other names

TGS1RNA guanine-7 methyltransferase TGS1snRNA/snoRNA cap hypermethylase[2]Trimethylguanosine synthase[4]

Not applicable for approved drugs, but preclinical approaches would involve inhibition of RNA cap hypermethylation to alter non-canonical translation pathways (as in cancer models)[5].