http://http://dspace.unitus.it:80 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 19 May 2013 07:43:56 GMT 2013-05-19T07:43:56Z http://hdl.handle.net/2067/1619 Title: The PDI (Protein Disulfide Isomerase) gene family in wheat. Authors: d'Aloisio, Elisa; Tanzarella, Oronzo A.; Dhanapal, Arun Prabhu; Porceddu, Enrico; Ciaffi, Mario Abstract: The PDI (Protein Disulfide Isomerase) gene family includes several members whose products are responsible for diversified metabolic functions. PDI and PDI-like proteins differ for number and position of thioredoxin-like (TRX-like) active (a type) and inactive (b type) domains, for presence/absence of other domains and of the KDEL signal of retention in the endoplasmic reticulum (ER). The phylogenetic analysis of typical PDI and PDI-like protein sequences resolved them into 10 groups (1), 5 of them (I-V) had 2 TRX-like active domains, whereas the remaining ones owned only a single TRX-like active domain (VI-VIII, QSOX and APRL). In particular, QRX and APRL were not included in this study due to their putative non-isomerase enzymatic activities encoded by an additional domain. The aim of the present research was the study of the complexity and diversity of the PDI gene family in wheat, with particular focus on the genes encoding PDIlike proteins structurally similar to TaPDIL1-1 (group I), the first identified and best characterized member of the PDI family, also named typical PDI. The most important function of typical PDI is the formation and isomerization of disulfide bonds during protein folding, which are accomplished by its two active TRX-like sites sharing the characteristic tetrapeptide –CGHC-. Several studies of molecular characterization, expression analysis and cell localisation in rice and maize have suggested the involvement of typical PDI in the assembly and deposition of storage proteins in these species (2, 3, 4). The characterization and chromosome location of the three homoeologous gene sequences encoding typical PDI and of their promoter sequences have been reported previously (5). Mon, 31 Dec 2007 23:00:00 GMT http://hdl.handle.net/2067/1619 2007-12-31T23:00:00Z http://hdl.handle.net/2067/1609 Title: The Protein Disulfide Isomerase gene family in bread wheat (T. aestivum L.) Authors: d'Aloisio, Elisa; Paolacci, Anna Rita; Dhanapal, Arun Prabhu; Tanzarella, Oronzo A.; Porceddu, Enrico; Ciaffi, Mario Abstract: Background: The Protein Disulfide Isomerase (PDI) gene family encodes several PDI and PDI-like proteins containing thioredoxin domains and controlling diversified metabolic functions, including disulfide bond formation and isomerisation during protein folding. Genomic, cDNA and promoter sequences of the three homoeologous wheat genes encoding the "typical" PDI had been cloned and characterized in a previous work. The purpose of present research was the cloning and characterization of the complete set of genes encoding PDI and PDI like proteins in bread wheat (Triticum aestivum cv Chinese Spring) and the comparison of their sequence, structure and expression with homologous genes from other plant species. Results: Eight new non-homoeologous wheat genes were cloned and characterized. The nine PDI and PDI-like sequences of wheat were located in chromosome regions syntenic to those in rice and assigned to eight plant phylogenetic groups. The nine wheat genes differed in their sequences, genomic organization as well as in the domain composition and architecture of their deduced proteins; conversely each of them showed high structural conservation with genes from other plant species in the same phylogenetic group. The extensive quantitative RT-PCR analysis of the nine genes in a set of 23 wheat samples, including tissues and developmental stages, showed their constitutive, even though highly variable expression. Conclusions: The nine wheat genes showed high diversity, while the members of each phylogenetic group were highly conserved even between taxonomically distant plant species like the moss Physcomitrella patens. Although constitutively expressed the nine wheat genes were characterized by different expression profiles reflecting their different genomic organization, protein domain architecture and probably promoter sequences; the high conservation among species indicated the ancient origin and diversification of the still evolving gene family. The comprehensive structural and expression characterization of the complete set of PDI and PDI-like wheat genes represents a basis for the functional characterization of this gene family in the hexaploid context of bread wheat. Description: L'articolo é disponibile sul sito dell'editore: http://www.biomedcentral.com Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2067/1609 2009-12-31T23:00:00Z http://hdl.handle.net/2067/1621 Title: Protein disulfide isomerase gene family in wheat: genomic structure, phylogenetic and expression analyses. Authors: Ciaffi, Mario; Paolacci, Anna Rita; d'Aloisio, Elisa; Dhanapal, Arun Prabhu; Tanzarella, Oronzo A.; Porceddu, Enrico Abstract: PDI and PDI-like proteins are responsible for multiple metabolic functions, including secretory protein folding, chaperone activity and redox signalling. Most studies on their diversified metabolic roles have been carried out in mammalians, whereas in plants the knowledge on the structural and functional features of these proteins and of their encoding genes is much less extensive. The purpose of the present research was the cloning and characterization of the genes encoding PDI and PDI like proteins in bread wheat and the comparison of their structure and expression with those of homologous genes isolated in other plant species. Former studies in wheat and other cereal species had been restricted to the genes encoding the typical PDI, which may accomplish an important role in the folding and deposition of seed storage proteins. Since wheat flour quality is strongly affected by composition and structure of seed storage proteins, the potential involvement of the PDI and of some PDI-like proteins of wheat in the seed storage protein folding and in the formation of intra- and inter-molecular disulfide bonds makes their study particularly interesting. Fourteen wheat cDNA sequences of PDI-like genes were amplified and cloned; eight of them were relative to distinct PDI-like genes, whereas six corresponded to homoeologous sequences. Also the genomic sequences of the eight non-homoeologous genes were amplified and cloned. Phylogenetic analyses, which included the eight PDI-like genes cloned in this research and the typical PDI gene, assign at least one of them to each of the eight major clades identified in the phylogenetic tree of the PDI gene family of plants. Although not probable, the presence of additional wheat genes of the PDI family can not be ruled out. The genes of the wheat PDI family were located in chromosome regions syntenic with the chromosome locations of their rice homologs, confirming their close syntenic relationships. Within the same phylogenetic group a high level of conservation, in terms of sequence homology, genomic structure and domain organization, was detected between the wheat sequences and those of the compared plant species. The wheat proteins of five groups (I-V) have two thioredoxin-like active domains and show structural similarities to the corresponding proteins of higher eukaryotes, whereas those of the remaining three groups (VI-VIII) contain a single thioredoxin-like active domain. Phylogenetic analysis showed that the complete set of PDI and PDI-like genes was already present in P. patens and that extended phenomena of duplication events have characterized the evolution of this gene family in different plant taxa. The comparison of the exon/intron structure showed a very similar genomic organization across the analysed species, including P. patens, whereas the alga C. reinhardtii showed a different intron/exon structure. The high conservation level of sequence and genomic organization within the PDI gene family, even between distant plant species, might be ascribed to the key metabolic roles of their protein products. The expression analysis of the nine non-homoeologous wheat genes, which was carried out by quantitative real time RT-PCR (qRT-PCR) in a set of 29 samples including tissues, developmental stages and temperature stresses, showed their constitutive, even though highly variable transcription rate. The comprehensive structural and expression characterization of the complete set of PDI and PDI-like genes of wheat performed in this study represents a basis for future functional characterization of this gene family in the hexaploid context of bread wheat. Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2067/1621 2009-12-31T23:00:00Z