title: Comparative phylogenetic analysis of cystatin gene families from arabidopsis, rice and barley.
abstract: The plant cystatins or phytocystatins comprise a family of specific inhibitors of cysteine proteinases. Such inhibitors are thought to be involved in the regulation of several endogenous processes and in defence against pests and pathogens. Extensive searches in the complete rice and Arabidopsis genomes and in barley EST collections have allowed us to predict the presence of twelve different cystatin genes in rice, seven in Arabidopsis, and at least seven in barley. Structural comparisons based on alignments of all the protein sequences using the CLUSTALW program and searches for conserved motifs using the MEME program have revealed broad conservation of the main motifs characteristic of the plant cystatins. Phylogenetic analyses based on their deduced amino acid sequences have allowed us to identify groups of orthologous cystatins, and to establish homologies and define examples of gene duplications mainly among the rice and barley cystatin genes. Moreover, the absence of a counterpart between the two monocots, as well as strong variations in the motifs that interact with the cysteine proteinases, may be related to a species-specific evolutionary process. This cystatin classification should facilitate the assignment of proteinase specificities and functions to other cystatins as new information is obtained.
authors.affiliation: Departamento de Biotecnología-UPM, Laboratorio de Bioquímica y Biología Molecular, ETS Ingenieros Agrónomos, Ciudad Universitaria s/n, 28040, Madrid, Spain. manuel@bit.etsia.upm.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Martínez
authors.forename: Zamira
authors.initials: Z
authors.lastname: Abraham
authors.forename: Pilar
authors.initials: P
authors.lastname: Carbonero
authors.forename: Isabel
authors.initials: I
authors.lastname: Díaz
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D015152:Blotting, Northern; D019295:Computational Biology; D015891:Cystatins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D018745:Genome, Plant; D001467:Hordeum / Q000235:genetics*; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D012984:Software; D013045:Species Specificity
chemical_list: D015891:Cystatins