Dugesia ¦Â Microtubule Proteins And Rab Proteins Cdna Library Cloning And Bioinformatics Analysis

The planarian Dujesia japonica is the representative species of Tricladida in the phylum Platyhelminthes, with body length 10-15 mm and a triangular head, and generally found in nature in the overcast cool fresh water. The morphological plasticity and regenerative capability have made them a good model animal in regeneration biology, neurobiology and developmental biology. In recent years, molecular biology and functional genomics have focused on Planarian. This research will help to reveal the common mechanism about evolution, development and regeneration in metazoan.In order to separate and identify the functional important genes from Dujesia japonica, the total RNA were extracted and used to constructed the cDNA library using SMARTTM cDNA Library Construction Kit. The average inserted cDNA fragments were about 1 kb, and the titer of cDNA library is 6×105cfu/ml.With the help of the bioinformatics to predict the deduced protein'structure and function, we identifiedβ-TUBLIN and RAS protein from the full length cDNA plasmid library.Theβtubulin gene sequence is 1539 bp in length, contains an ORF of 1335 base pairs and encodes a polypeptide of 444 residues with a predicted molecular weight about 49.7kD and pⅠ4.82. There is (3 tubulin signature sequence GGGTGSG and the two conserved amino acid sequence motifs NNWAKGHY at site 99 and RKAFLHWYTGEGMDEMEFTE at site 405 of deduced aminoacid. The analysis of phylogenetic relationship showed that the cloned gene has high amino acid sequences similarity of about 92%-96% with the other knownβtubulin in animals.Rab proteins are monomeric small GTP-binding proteins. The Rab gene sequence is 2141 bp, contains an ORF of 621 base pairs and encodes a polypeptide of 206 residues with a predicted molecular weight about 23.1kD and PI 6.59. Rab protein contain four guanine nucleotide binding domains(GNB), this domain plays a key role in molecular regulation, and are highly conserved among plants, yeasts and animals. The cloned gene has high amino acid sequences similarity of about 65%-75%with the other known Rab proteins in animals.