Non-POU domain-containing octamer-binding protein

NonO has been shown to interact with SFPQ, SPI1, and Androgen receptor. == Functions ==

NonO is involved with many nuclear processes and binds to both DNA and RNA. As with all DBHS proteins, NonO is described as a multifunctional nuclear protein. NonO is implicated in many biological functions including pre-mRNA splicing, activation of transcription, termination of transcription, DNA unwinding and pairing, and maintaining correct circadian clock function. NonO binds with the Rasd1 protein, and the resulting dimer is hypothesized to modulate the function of NonO to downregulate the expression of the CREB genes NR4A1 and NR4A2. NonO binds to SFPQ to form a heterodimer that interacts with the MATR3 protein. The interaction of these three proteins may be part of the process in the nucleus that is responsible for the retention of RNAs that are defective, not yet mature enough to be exported, or are designed to be retained in nucleus. == Gene location ==

NonO (Human) is encoded by the NONO gene which is located on the plus strand of the X chromosome. == Role in disease ==

Melanoma NONO has been shown to be more strongly expressed in melanoma cell lines and melanoma tissue samples compared to normal human cell lines and normal skin tissue. Studies have found that the knockout of NonO from melanoma cell lines results in both reduced proliferation rates of the cancer cells and a significant decrease in the potential migration of the cancer cells. Intellectual disability associated with non-compaction cardiomyopathy Studies in humans and mice have identified that NONO null mutations likely lead to the development of a clinically recognizable intellectual disability with cognitive and affective deficits. It was later found that these pathogenic variants were also strongly associated with cardiomyopathy with left ventricular noncompaction and sometimes Ebstein's anomaly. == Structure ==

As with other proteins of the DBHS family, NonO protein functions rarely functions alone and primarily forms homo- and heterodimers with other DBHS proteins to perform its various functions. It is theorized that these dimers may have different functions that are specific to the type of cell that they are found in. It is speculated that the phosphorylation state of NonO acts to direct the protein's many disparate functions within the nucleus. == Tissue specificity ==

NonO is found in the nucleus of most mammalian cells and is primarily distributed within the nucleoplasm, it can also be found concentrated within sub-nuclear domains known as paraspeckles. NonO has also been observed within the brain, localized in the cytoplasm of hippocampal neurons that are associated with RNA transport granules. It is also highly expressed within heart tissue. == Discovery ==

NonO was first discovered in 1993 by researchers at Cold Springs Harbor Laboratory. Due to the protein being originally identified as a RNA-binding protein it was named p54nrb for Nuclear RNA-binding protein, 54 kDa. == References ==