Tar DNA-binding protein 43 (TDP43) is a DNA and RNA-binding protein which regulates transcription and splicing. It is involved in the regulation of CFTR splicing. It promotes CFTR exon 9 skipping by binding to the UG repeated motifs in the polymorphic region near the 3'-splice site of this exon. The resulting aberrant splicing is associated with pathological features typical of cystic fibrosis. TDP43 may also be involved in microRNA biogenesis, apoptosis and cell division. TDP43 can repress HIV-1 transcription by binding to the HIV-1 long terminal repeat. Also, TDP43 stabilizes the low molecular weight neurofilament (NFL) mRNA through a direct interaction with the 3' UTR [taken from the Universal Protein Resource (UniProt) www.uniprot.org/uniprot/ Q13148].