Molecular characterization of gene sequences coding for protein disulfide isomerase (PDI) in durum wheat (Triticum turgidum ssp durum)

The organisation of the durum wheat genomic sequence (3.5 kb) coding for pr otein disulfide isomerase (PDI), deduced by comparison between genomic frag ments and cDNA sequences (1.5 kb) isolated from immature caryopses, is desc ribed. The gene structure consists of ten exons and nine introns. The prese nce of consensus sequences involved in splicing, such as intron-exon juncti ons and branchpoint, has been observed and discussed. Although the deduced wheat PDI amino acid sequence exhibited an overall identity of only 31% to that of human PDI, their modular architecture in terms of number, size, loc ation and secondary structure-propensities of the constituent domains are r emarkably similar. The comparison of the amino acid sequences with the eigh t available plant PDI-like sequences showed a high identity with four of th em and low with the remaining ones. Analyses of transcription levels showed that the PDI mRNA was present in all analysed tissues, with much higher ex pression in immature caryopses. (C) 2001 Elsevier Science B.V. All rights r eserved.