CST1 and cyst: These include the specific cyst wall glycoprotein (CST1), which is a structural component of the cyst wall (46), the nucleotide-sugar transporter 1 (NST1), necessary for the glycosylation of the cyst wall (47), or the Apetala-2 transcription factor AP2XI-4, which is important for bradyzoite gene expression during conversion and cyst formation (48).