Examining the potential involvement of NONO in TDP-43 proteinopathy in
Drosophila
Abstract
The misfolding and aggregation of TAR DNA binding protein-43 (TDP-43),
leading to the formation of cytoplasmic inclusions, emerge as a key
pathological feature in a spectrum of neurodegenerative diseases,
including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar
dementia (FTLD). TDP-43 shuttles between the nucleus and cytoplasm but
forms nuclear bodies (NBs) in response to stress. These NBs partially
colocalize with nuclear speckles and paraspeckles that sequester RNAs
and proteins, thereby regulating many cellular functions. The laboratory
of Steven Brown has recently found that the non-POU domain-containing
octamer-binding protein (NONO), a component of paraspeckles, forms novel
nuclear speckle-like structures in mouse cortical neurons in response to
stress and sleep deprivation. These findings suggest the possibility of
a functional link between NONO and TDP-43, potentially contributing to
TDP-43 proteinopathy. Here, we demonstrate that loss of function in the
Drosophila homolog of NONO, no on or off transient A (NonA), exacerbates
pathological phenotypes caused by TDP-43 gain of function, leading to
locomotor defects and life span shortening. These results provide
supporting evidence for the functional link between NONO and TDP-43 and
lay the foundation for dissecting underlying mechanisms.