gld2

GLD2 is a term used for a family of cytoplasmic poly(A) polymerases that add poly(A) tails to selected messenger RNAs in the cytoplasm, influencing mRNA stability and translation. It is a member of the noncanonical poly(A) polymerase group and is conserved across eukaryotes, where it participates in post-transcriptional regulation of gene expression.

In Caenorhabditis elegans, gld-2 encodes a cytoplasmic poly(A) polymerase that forms a functional complex with gld-3 to promote polyadenylation of specific maternal mRNAs during oogenesis. This tail elongation enhances translation and supports proper germline development. Disruption of gld-2 or gld-3 leads to defects in oogenesis and fertility. Similar cytoplasmic polyadenylation systems exist in other species, including insects, where GLD-2–like enzymes contribute to translational activation by tail lengthening.

In humans and other vertebrates, GLD-2 homologs, commonly referred to by the gene symbol PAPD4, function as cytoplasmic poly(A) polymerases that participate in mRNA tailing and RNA metabolism. They can cooperate with cytoplasmic polyadenylation factors such as CPEB to regulate tail length and translation of specific transcripts, particularly during development and cellular responses. The exact range of GLD-2–dependent activities in human cells is an area of ongoing research and may include roles in microRNA tailing and RNA silencing pathways.

The GLD2 designation is used across species to denote related enzymes that promote cytoplasmic polyadenylation and translational control. In humans, PAPD4 is the gene most commonly associated with this activity, with GLD2 serving as an alias in some contexts.