Nakashima K, Yamada L, Satou Y, Azuma J, Satoh N.

Dev Genes Evol. 2004 Feb;214(2):81-8.

The evolutionary origin of animal cellulose synthase.

The cellulose synthase genes in Tunicates are thought to be of actinobacterial origin, because the tunicate CesA gene contains two domains with similarity with a cellulose synthase and a cellulase of the glycoside hydrolase (GH)-6 family, and these genes are often found in proximity in actinobacteria.