Synonyms: Background:Beta-1,3-N-acetylglucosaminyltransferase that plays a key role in the synthesis of lacto-or neolacto-series carbohydrate chains on glycolipids, notably by participating in biosynthesis of HNK-1 and Lewis X carbohydrate structures. Has strong activity toward lactosylceramide(LacCer) and neolactotetraosylceramide(nLc(4)Cer, paragloboside), resulting in the synthesis of Lc(3)Cer and neolactopentaosylceramide(nLc(5)Cer), respectively. Probably plays a central role in regulating neolacto-series glycolipid synthesis during embryonic development.