Poly A Binding Protein Nuclear 1 (PABPN1)

PABPN1 encodes an abundant nuclear protein that binds with high affinity to nascent poly(A) tails. The protein is required for progressive and efficient polymerization of poly(A) tails on the 3""" ends of eukaryotic genes and controls the size of the poly(A) tail to about 250 nt. At steady-state, this protein is localized in the nucleus whereas a different poly(A) binding protein is localized in the cytoplasm.An expansion of the trinucleotide (GCG) repeat from normal 6 to 8-13 at the 5""" end of the coding region of this gene leads to autosomal dominant oculopharyngeal muscular dystrophy (OPMD) disease. Multiple splice variants have been described but their full-length nature is not known. One splice variant includes introns 1 and 6 but no protein is formed.