Molecular cloning and characterization of a cotton glucuronosyltranferase gene.

A glucuronosyltranferase gene has been isolated from cotton (Gossypium hirsutum) fiber cells using rapid amplification of the cDNA ends. The full-length cDNA, designated GhGlcAT1, is 1400 bp in length (AY346330) and contains an open reading frame of 1107 bp encoding a protein of 368 amino acids. Alignment of the GhGlcAT1 predicted amino acid sequence was shown to have high sequence similarity with animal glucuronosyltranferases. A phylogenic tree generated by the PHYLIP program package showed that GhGlcAT1 is clustered into the plant glucuronosyltranferase proteins and is distinct from those of other species. Homology modeling of the GhGlcAT1 structure using Homo sapiens native glucuronosyltranferase (1 kws and 1 fgg) structure as a template strongly suggests that the main-chain conformation and the folding patterns were similar to structural features characteristic of animal glucuronosyltranferases. Northern blot analysis showed that the transcripts of GhGlcAT1 were abundant in fiber cells, moderate in stem, but not detected in ovule, flower, seed, root and leaf. Transcripts were most abundant at 15dpa fiber. The transcription occurred at both the primary wall elongation stage and former stage of secondary cell thickening, suggesting that GhGLcAT1 may be involved in non-cellulose polysacchrides biosynthesis of the cotton cell wall.