The human soluble neuropilin-1 (sNRP) polyadenylation signal (sNRP-poly(A)), situated downstream of the GT splice donor site of intron 12 of the full-length neuropilin-1 gene, also functions as the termination codon for sNRP. This 17 nucleotide sequence efficiently facilitates addition of poly(A) tails to RNAs expressed in cells. The present invention shows that this optimally succinct sequence has similar activity to the SV40 polyadenylation signal that is currently used in expression vectors. By using this shorter dual termination/polyadenylation signal and avoiding the need for large and cumbersome polyadenylation signals, expression vectors may be engineered to carry considerably larger genes.