The gene at thewaxy (wx)locus in rice was cloned and the nucleotide sequence of the coding region was determined. Thewx+gene from rice was composed of a number of exons and in-trons. The deduced amino acid sequence indicated that the predicted polypeptide is composed of a putative transit peptide of 77 amino acids and a mature protein region of 532 amino acids. The putative transit peptide, which may be essential for transporting the product of the gene at thewxlocus(wx+protein) into the amyloplast, has some characteristic features similar to those of the transit peptide associated with proteins to be transported into the chloroplast. An antiserum against the ricewx+protein (anti-WXP serum) was prepared and the expression of thewxlocus was examined by the Northern blotting analysis using DNA cloned from the ricewxlocus and by the immunoblotting analysis using the anti-WXP serum. The expression of thewx+gene was regulated in a tissue-specific manner, namely, it was expressed only in the endosperm and pollen. Thewx+gene was active at the early and middle stages and was almost inactive at the late stage of seed development. During active transcription of the gene, thewx+protein appears to accumulate linearly.
展开▼
