Cellulose Synthase-like Genes

HAZEN, S.P., SCOTT-CRAIG, J.S., WALTON, J.D., Cellulose synthase-like genes of rice, Plant Physiol., 2002,128, 336-340. 

Wang X., Cnops G., Vanderhaeghen R., De Block S., Van Montagu M., and Van Lijsebettens M. 2001. AtCSLDS, a cellulose synthase-like gene important for root hair growth in Arabidopsis. Plant Physiol 126 575-586. 

Samuga A. and Joshi C.P. 2004. Cloning and characterization of cellulose synthase-like gene, PtrCSLD2 from developing xylem of aspen trees. Physiol Plant 120(4) 631-641. 

Liepman, A. H., Wilkerson, C. G., and Keegstra, K., Expression of cellulose synthase-like (Csl) genes in insect cells reveals that CslA family members encode mannan synthases. PNAS USA 2005, 102 (6), 2221-2226. 

In terms of quantity, probably cellulose (O Chap. 6.3) is the most important plant polysaccharide and has a key role in maintaining the cell wall. Enz)me complexes, with perhaps 36 subunits, produce this polymer and a number of the relevant CESA (cellulose synthase) genes have been identified defects in some CESA genes are associated with some irx (irregular xylem) phenot) es [323]. Related proteins, encoded by cellulose synthase-like A(CslA) genes, are apparently /3-mannan synthases [324]. Mannans are only one of the many hemicellu-... 

Favery B., Ryan E., Foreman J., Linstead P, Boudonck K., Steer M., Shaw P., and Dolan L. 2001. KOJAK encodes a cellulose synthase-like protein required for root hair cell morphogenesis in Arabidopsis. Genes Dev 15 79-89. 

Neill A.A. 2005. A Cellulose synthase-like (CslD) gene from Coleochaete scutata. M.S. University of Rhode Island... 

Arabidopsis, cellulose synthase (CESA), cellulose synthase-like (CSL), gene expression, predicted proteins. 

These observations suggest a lateral transfer of cellulose synthase from cyanobacteria to D. discoideum. However, while the primary and secondary endo-symbiotic events that led to the evolution of plastids in plants and algae provide a clear mechanism for the transfer of a cyanobacterial cellulose synthase to photosynthetic organisms, such a mechanism is lacking for D. discoideum. Cyanobacterial genes are known to exist in eukaryotes which have secondarily lost plastids. However, there is no evidence for the existence of an endosymbiotic relationship between ancestors of D. discoideum and a cyanobacterium. Therefore, if a lateral transfer occurred, it was likely xenologous, possibly via a food ratchet mechanism (Doolittle 1998). 

The proliferation of complete genome sequences in public databases provides an additional means to track the evolution of cellulose in bacteria. Conservation of operons and/or gene clusters (synteny) can be used to trace not only the history of cellulose synthase, but also its associated proteins. The existence of a few these gene clusters has been well documented. In the sections below, I would like to give a brief review of the known gene organizations and introduce two novel ones which may be linked to the eukaryotic acquisition of cellulose biosynthesis. 

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