Malat

Malat is commonly used as shorthand for MALAT1, a long noncoding RNA (lncRNA) gene originally linked to metastasis in lung adenocarcinoma. The MALAT1 locus produces a transcript that is abundantly expressed in many tissues and localized to nuclear speckles, subnuclear structures involved in RNA processing.

Molecular characteristics and processing: MALAT1 transcripts are typically very long, and a portion of the locus is processed by RNase P to generate a small tRNA-like RNA called mascRNA, while the remaining sequence remains as the MALAT1 lncRNA. The MALAT1 RNA is predominantly nuclear and is thought to influence gene expression and RNA processing through interactions with splicing factors.

Function and mechanisms: A widely discussed mechanism is MALAT1’s association with serine/arginine-rich (SR) splicing factors, where MALAT1 is proposed to modulate the phosphorylation state and activity of these splicing regulators, thereby affecting alternative splicing of numerous transcripts. In addition, MALAT1 may have roles in transcriptional regulation and chromatin state, though the full spectrum of its functions remains an active area of research. The exact physiological relevance of MALAT1 can be context-dependent, and mechanisms are not fully resolved.

Clinical relevance and research status: MALAT1 is frequently studied in cancer research due to its initial linkage to metastasis. In some models, altered MALAT1 expression correlates with changes in migration, invasion, and metastatic potential, but results are variable across cell types and experimental systems. Mouse models lacking MALAT1 are viable, indicating it is not essential for development, although tissue-specific effects have been reported. MALAT1 remains a focal point for understanding RNA-based regulation of gene expression and cancer biology.

See also: long noncoding RNA; nuclear speckles; SR splicing factors.