Fig. 2.

In trophoblasts, ST8SiaIV synthesizes N-linked polySia. (A) Trophoblast-specific expression of the two polysialyltransferase enzymes, ST8SiaII and ST8SiaIV, was determined by relative RNA quantification using the Affymetrix Gene ST 1.0 exon array platform. iCTBs; invasive cytotrophoblasts. pCTBs; progenitor cytotrophoblasts. (B) First-trimester, 7-week human placental lysates were treated with PNGase F, separated by SDS–PAGE and immunoblotted with anti-polySia mAb 735 (left). MB lysates were included as a positive control (right).