Mtrex, also known as MTR4, is a Ski2-like RNA helicase. It plays a central role in RNA surveillance and degradation pathways as an activator of the RNA exosome. This function is crucial as it affects various biological processes by regulating RNA substrates that are presented to the exosome [1].

In HIV-1 latency, MTR4, along with MATR3, is involved in the regulation of unspliced HIV-1 RNA. They co-exist in a ribonucleoprotein complex, with MTR4 degrading the RNA while Rev controls this regulatory switch. Also, MTR4 is part of a network of nuclear RNA surveillance factors that silence HIV-1 transcription. Knocking down MTR4 in relevant cells increases HIV-1 expression, indicating its role in maintaining latency [2,3].

In the context of long non-coding RNA (lncRNA) regulation, MTR4 forms a complex with hnRNPH1 to regulate the stability of NEAT1v2, which is important for IL8 expression [4]. Moreover, in ribosome biogenesis, the MTR4 adaptor PICT1 functions in two distinct pre-rRNA processing steps in human cells [5].

In conclusion, Mtrex (MTR4) is essential for RNA surveillance and degradation. Its functions in regulating RNA in processes like HIV-1 latency, lncRNA stability, and ribosome biogenesis highlight its significance. Studies related to Mtrex, especially those using loss-of-function models, help in understanding its role in diseases such as HIV-1-related latency, potentially providing new therapeutic intervention strategies.