Articular cartilage repair is limited. Current treatments for cartilage defect are less satisfactory, and rarely restore full function or return the tissue to its native normal state. The rise of tissue engineering holds great promise for the generation of functional cartilage tissue substitutes. The history of cartilage tissue engineering and highlights the applications and advantages of various kinds of scaffolds in cartilage tissue engineering, such as native scaffolds, synthesis scaffolds, composite scaffolds and nanometer scaffolds had been introduced. But native scaffolds have weak strength and immunogenicity insufficiency, synthesis scaffolds degrade quickly, whose degrading products have cytotoxicity,which need further improvement. The application of superficial decoration overcomes the disadvantage of some scaffolds to an extend. Composite scaffolds possess the advantages of several scaffolds, it points out the direction of future scaffolds research. The development of Nanometer technique endows newly-synthesis scaffolds with nano-grade, thus it has some advantages and give a new way for the development of tissue engineering. At the end, the problems of these scaffolds, their trend of development and perspective studies were discussed.

Objective To screen and clone the target genes transactivated by hepatitis C virus (HCV) core protein. Methods The mRNA was isolated from HepG2 cells transfected with pcDNA3.1(-)-core and pcDNA3.1(-) empty vector, respectively, and suppression subtractive hybridization (SSH) method was employed to analyze the differentially expressed DNA sequences of the two groups. The obtained sequences were searched for homologous DNA sequence from GenBank. One of them was confirmed to be a new gene without homology with known genes in this database.Then, electric polymerase chain reaction was conducted for the cloning of the full-length DNA of the new gene, in conjunction with Kozak rule and the existence of polyadenyl signal sequence. The reverse transcription PCR (RT-PCR) was used to amplify the new gene with mRNA from HepG2 cell as the template. The coding sequence for the new gene was deduced according to the nucleotide sequence. Results A new gene with unknown function was named TAHCCP1.The nucleotide sequence of the new gene and its corresponding protein-encoding amino acid, which was 2 001nt and composing 667aa, have been determined. The sequence of the TAHCCP1 gene has been registered in GenBank with its accession number AY038359. Conclusion TAHCCP1 gene transactivated by HCV core protein was cloned and identified successfully by a combination of molecular biological technology and bioinformatics technique. The results are expected to pave the way for the study of the molecular mechanism of the transactivating effects of HCV core protein and the development of new therapies for chronic hepatitis C.

Objective To screen the genes differentially expressed in gene expression in human lymphoma cell line Jurkat cells treated with phosphonoformate (PFA). Methods cDNA microarray technique was employed to detect the mRNA expressed in Jurkat cells treated with PFA or 0.9 percent sodium chloride, respectively. Results Among 1 152 genes there were 94 genes with different expression, of which 38 genes were upregulated and 56 genes were downregulated in Jurkat cells treated with PFA compared with those treated with 0.9 percent sodium chloride. Conclusions cDNA microarray technique was successfully used to screen the genes with different expression in Jurkat cells treated with PFA, and the results brought some new clues for the study of the immune regulation mechanism of PFA.

Objective To screen and clone the target genes transactivated by nonstructural protein 5A (NS5A) of hepatitis C virus (HCV). Methods The mRNA was isolated from HepG2 cells transfected with pcDNA3.1(-)-NS5A and pcDNA3.1(-) empty vector, respectively. Suppression subtractive hybridization (SSH) method was employed to analyze the differentially expressed DNA sequence between the two groups. The obtained sequences were searched for homologous DNA sequence from GenBank. The new gene with no homology with known genes in this database was confirmed, and electric polymerase chain reaction was conducted for cloning the full-length DNA of the new gene and in conjunction with Kozak rule and the terminus of polyadenyl signal sequence. The reverse transcription PCR (RT-PCR) was used to amplify the new gene from mRNA of HepG2 cell as the template. The coding sequence of the new gene was deduced according to the nucleotide sequence. Results A new gene with unknown function was named as NS5ATP3. The nucleotide sequence of the NS5ATP3 gene and its corresponding amino acid have been determined, which contained 1 572nt and 524aa. The sequence of the NS5ATP3 gene was deposited into GenBank, with the accession number AF529364. Conclusions NS5ATP3 gene transactivated by HCV NS5A protein was cloned and identified successfully by combining molecular biological technology and bioinformatics technique. These results will pave the way for the study of the molecular mechanism of the transactivating effects of HCV NA5A protein and the development of new therapy for chronic hepatitis C.

Objective To construct a subtractive cDNA library of genes differentially expressed in human lymphoma cell line Jurkat cells treated with phosphonoformate (PFA), and to clone genes associated with its immune regulation. Methods Using suppression subtractive hybridization (SSH) technique, the mRNA was isolated from Jurkat cells treated with phosphonoformate or 0 9 percent sodium chloride, respectively, and then cDNA was synthesized. After restriction enzyme RsaI digestion, small sized cDNAs were obtained. Then tester cDNA was subdivided into two portions and each was ligated with different cDNA adaptor. The tester cDNA, which was hybridized with driver cDNA twice and amplified by nested polymerase chain reaction (PCR) twice, was subcloned into T/A plasmid vectors to set up the subtractive cDNA library. Amplification of the library was carried out with E. coli strain JM109. The clones, which were selected randomly, were amplified by PCR, and then they were sequenced and analyzed in GenBank with Blast search. Results The subtractive cDNA library of genes differentially expressed in Jurkat cells treated with PFA was constructed successfully. The amplified library contained 46 positive clones, which contained 200- 1 000 bp of inserts. Fourteen clones were analyzed by sequencing and bioinformatics, which were identified as eleven known genes and three genes with unknown function. Conclusions The subtractive cDNA library of genes differentially expressed in Jurkat cells treated with PFA using SSH technique was constructed successfully, which brought some new clues for the study of the immune regulation mechanism of PFA

Objective To explore the influence of XTP4 on genomic expression profile of hepatocyte through screening and cloning of genes trans-regulated by XTP4-expressing plasmid. Methods The expressive vector pcDNA3.1(-)-XTP4 was constructed by routine molecular biological methods, and suppression subtractive hybridization (SSH) method was employed to detect the mRNA differentially expressed by the HepG2 cells transfected with pcDNA3.1(-)-XTP4 and pcDNA3.1(-), respectively, using lipofectamine. The twice enriched PCR products were subcloned into T/A vectors to set up the subtractive library. Amplification of the library was carried out in E. coli strain JM109. The screened cDNA were sequenced and analyzed in GenBank with Blast search after PCR. Results The amplified subtractive library containd 21 positive clones. Colony PCR analysis showed that there were 16 clones containing 200-1000bp inserts. Sequence analysis was performed and 9 kinds of encoding sequences were achieved. These genes trans-regulated by XTP4 protein involved in hepatic fibrogenesis, tumorgenesis, mitochondrial function, and cell growth regulation. Conclusions The findings obtained by SSH provide significant data for a preliminary understanding of the biological function of a new identified gene-XTP4. These results will pave the way for the study of the molecular mechanism of the transactivating effects of HBxAg and the development of new therapy for chronic hepatitis B.

Objective To construct a subtractive cDNA library of genes differentially expressed in human lymphoma cell line Jurkat cells treated with glycyrrhizin (GL), and to clone genes associated with its immunological regulation, and to further elucidate the molecular immune mechanism of GL. Methods The mRNA was isolated from Jurkat cells treated with either GL or 0.9 percent sodium chloride as a control, then cDNA was synthesized. Suppression subtractive hybridization (SSH) method was employed to analyze the differentially expressed DNA sequence between the two groups. The cDNA was sequenced and analyzed in GenBank with Blast search after the amplification of the subtractive library by PCR. Results The amplified library contained 28 positive clones. Colony PCR analysis showed that there were 22 clones containing 200-1 000 bp inserts. Sequence analysis was performed, and the full length sequences were obtained with bioinformatics method. Altogether 11 kinds of encoding sequences were achieved, including interleukin-12, interleukin-18, and thymosin ?1, etc. Conclusions A subtractive cDNA library of genes differentially expressed in Jurkat cells treated with GL using SSH technique was constructed successfully, and it might give some new clues for the study of the immune regulation mechanism of GL.

Objective To clone amastin coding genes from different strains of Leishmania parasites. Methods Using amastin cDNA sequence as the reference, dbEST data base established by National Center Biotechnology Information (NCBI), USA, was searched by BLAST tool. A 309 bp DNA fragment of Leishmania major was found and used as the probe for the screening of a DNA library. The amastin gene of Leishmania major Abdou was cloned and sequenced. Specific primers were designed and amastin genes for Leishmania mexicana WR972, Leishmania brizeliensis and Leishmania amazonensis joseph were amplified by polymerase chain reaction. Results The amastin genes from 4 strains of Leishmania parasites were cloned and sequenced. It was found that all 4 amastin genes contained unique open reading frame of 552 bp and encoded amastin protein of 183 amino acid residues. Conclusion The amastin genes of 4 strains of Leishmania parasites were successfully cloned.

To construct a cDNA subtractive library of genes transactivated by hepatitis C virus core protein with suppression subtractive hybridization technique. mRNA was isolated from HepG2 cells transfected with pcDNA3 1(-)-core and pcDNA3 1(-) empty vector,respectively, then cDNA was synthesized. After restriction enzyme RsaI digestion, small sized cDNA were obtained. Then tester cDNA was divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR, and then it was subcloned into T/A plasmid vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain JM109. The cDNA were sequenced and analyzed in GenBank with Blast search after PCR. The subtractive library of genes transactivated by HCV core protein was constructed successfully. The amplified library contained 233 positive clones. Colony PCR product showed that 213 clones contained 100~ 1 000 bp inserts. Sequence analysis was performed in 63 clones. Six of the sequences were unknown genes before. The full length sequences were obtained with bioinformatics method,which had been accepted by GenBank. It suggested that six novel cDNA sequences might be target genes transactivated by HCV core protein.

Objective To construct a cDNA subtractive library of genes transactivated by c-terminally truncated middle surface protein of hepatitis B virus(MHBs t) with suppression subtractive hybridization technique for cloning genes associated with transactivation. Methods The mRNA was isolated from HepG2 cells transfected with pcDNA3.1(-)-Mt167 and pcDNA3.1(-) empty vectors, respectively, then cDNA was synthesized. After restriction enzyme Rsa I digestion, small-size cDNAs were obtained. Then tester cDNA was divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR and then was subcloned into T/A plasmid vectors to set up the subtractive library. Amplification of the library was carried out with E. coli strain JM109. The cDNA was sequenced and analyzed in GenBank with Blast search after PCR. Results The subtractive library of genes transactivated by MHBs t was constructed successfully. The amplified library contained 94 positive clones. Colony PCR showed that these clones contained 200-800bp inserts. Sequence analysis was performed in 50 clones,and the full length sequences were obtained with bioinformatics method. 23 coding sequences were obtained in total, which consisted of 19 known and 4 unknown ones.Conclusions The obtained sequences may be target genes transactivated by MHBs t, among which some genes coding proteins may involve in cell cycle regulation, immune response and tumour genesis.