Characterization of the PSG11 Gene

The pregnancy-specific β1-glycoproteins (PSG) form the major group of proteins synthesized in the human placenta. There are over 30 proteins in the family, encoded by 11 genes located on chromosome 19q13.1-13.3. The genes can be divided into three subgroups based on the C-terminal exons expressed. The subgroup 1 genes have been well characterized. In this study the organization and sequence of a complete, functional, subgroup 3 gene is described. It contains the C-terminal exons, Cw, Cr, and Cs, which are expected from the transcripts characterized. Downstream from these exons are sequences homologous to the C-termini of the subgroup 1 type genes. This demonstrates that the subgroup 1, 2, and 3 genes are related via insertions/deletions. Comparison of the C-terminal sequences of the three subgroups of genes shows that the subgroup 2 and 3 genes are more closely related than, and are distinct from, the subgroup 1 genes.