Cytoplasmic poly(A) RNA polymerase that adds successive AMP monomers to the 3'-end of specific RNAs, forming a poly(A) tail. In contrast to the canonical nuclear poly(A) RNA polymerase, it only adds poly(A) to selected cytoplasmic mRNAs. May not play a role in replication-dependent histone mRNA degradation (By similarity). ATP + RNA(n) = diphosphate + RNA(n)-3'-adenine ribonucleotide Belongs to the DNA polymerase type-B-like family. GLD2 subfamily.