TAR DNA-binding protein 43 (TDP-43) is a DNA and RNA-binding protein which regulates transcription and splicing. TDP-43 is involved in the regulation of CFTR splicing, and promotes CFTR e, Xenopus/Amphibian,on 9 skipping by binding to the UG repeated motifs in the polymorphic region near the 3'-splice site of this e, Xenopus/Amphibian,on. The resulting aberrant splicing is associated with pathological features typical of cystic fibrosis. TDP-43 is also involved in microRNA biogenesis, apoptosis, and cell division. TDP-43 can repress HIV-1 transcription by binding to the HIV-1 long terminal repeat.