Dyneins are a group of evolutionarily highly conservative molecular proteins,which can be divided into two groups:cytoplasmic dyneins and axonemal dyneins.Cytoplasmic dynein probably moves along the microtubule essential for transporting cargo in eukaryotes.It is also probably involved in the movement of chromosomes and positioning the mitotic spindles for cell division.Dynein light chain 2,cytoplasmic,is a protein that in humans is encoded by the Dynll 2 gene.To clone dynein light chain,LC8-type 2(Dynll 2)gene from A.davidianus,and to analyze the characteristics of the functional gene by bioinformatics analysis,the structure of Dynll 2 gene was isolated from skin cDNA library.A cDNA library of the skin tissue was constructed by using the isolated mRNA as the template during reverse transcription.The skin cDNA library of A.davidianus were detected and sequenced by picking clones randomly.It was confirmed that the titer of the skin cDNA library of A.davidianus was 1.50×10⁶ cfu,the recombination rate was 94.8%,and the PCR results showed that the average size of inserts segment was about 1 000 bp.A total of 343 ESTs from the library were sequenced and made alignment with sequences in GenBank database.Moreover,at least 214 clones(Evalue＜10^-6)derived from these identified clones were categorized into nine categories.Immune-related genes accounted for 31.3% of the largest distribution,metabolism genes(14.0%),cytoskeleton genes(13.0%)and signaling pathway-related genes(12.6%) took up a larger gene distribution though.It revealed that skin of A.davidianus made intense activities in the form of secretions and took part in metabolism reactions,according to their physiology function in the area of immunity,breathing,and osmotic pressure equilibrium.In order to investigate the contribution of Dynll 2 to motor protein in A.davidianus,molecular cloning,analyzing cDNA sequence and expression analysis of Dynll 2gene from A.davidianus were performed.The relative mRNA expression levels of Dynll 2 gene were investigated in A.davidianus using real-time RT-PCR.The Dynll 2cDNA contained a 682 nt of continuous complete open reading frame encoding a polypeptide of 104 amino acids with a calculated molecular mass of 12.03 ku.Analytic results of TMHMM,Phyre,Protscale and SMART showed that Dynll 2 localized to membrane.Dynll 2 contained conserved “ZnFC2H2” motif of Dynein family.Dynll 2 shared high amino acid sequence identity with other organisms and the tertiary structure of the Dynll 2 of A.davidianus was highly homologous to the one of Rattus norvegicus.Then phylogenesis analysis of Dynll 2 was obtained with other 26 animals,and it showed Dynll 2 of A.davidianus was highly homologous to terrestrial animals or freshwater fishes.Moreover,we were able to express Dynll 2 mRNA in 6 tissues of A.davidianus,followed by bowel,muscle,liver,lung,skin and stomach.The data of qRTPCR,analyzed by 2^-ΔΔCt method,indicated the plentiful presence of Dynll 2 mRNA in muscle rather than other 5 tissues.