Rosettes the machinery of cellulose synthesis

Sequence analyses revealed that the proteins encoded by the CesA genes belong to family 2 glycosyl transferases, which characteristically display a two-domain structure (Saxena et al. 1995 Saxena and Brown, Jr. 1997 Henrissat et al. 2001). The N-terminal A-domain contains the D...D(x)D motif common to all family 2 members. The C-terminal B-domain carries the QxxRW motif characteristic 

Similar to Arabidopsis, 10 different CesA genes were first identified (Djerbi et al. 2004) by analyzing EST sequences in a collection of tissue specific cDNA libraries of poplars (Sterky et al. 2004). These CesA genes were named PttCesA (for Populus tremula x tremuloides, Ptt) followed by a number (1-9) reflecting 

PttCesAl PttCesA2 PttCesA3-1 PttCesA3-2 PttCesA4 PttCesAS PttCeaAB PttCaaAT PttCesAS PttCesA9 

In this, it resembles the promoter of the xylem-specific PtrCesAl gene from Populus tremuloides, which is very similar to PttCesA3-l and PttCesA3-2, and which was shown to be activated by tension stress in transgenic tobacco expressing the promoter-P-glucuronidase (GUS) fusions (Wu et al. 2000). 

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