柑桔MADS盒APETALA1同源DNA片段克隆

用PCR扩增法 ,从柑桔基因组分离出了AP1同源基因中的一个片段。序列分析表明 ,它与其它植物的MADS盒基因同源性较高 ,氨基酸序列同源 4 5%～ 73% ,但是否与发育有关 。

Genetic alterations of hepatocellular carcinoma by random amplified polymorphic DNA analysis and cloning sequencing of tumor differential DNA fragment

AIM: To study the genetic alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC), and to find the tumor related DNA fragments.METHODS: DNA isolated from tumors and corresponding noncancerous liver tissues of 56 HCC patients was amplified by random amplified polymorphic DNA (RAPD)with 10 random 10-mer arbitrary primers. The RAPD bands showing obvious differences in tumor tissue DNA corresponding to that of normal tissue were separated,purified, cloned and sequenced. DNA sequences were analyzed and compared with GenBank data.RESULTS: A total of 56 cases of HCC were demonstrated to have genetic alterations, which were detected by at least one primer. The detestability of genetic alterations ranged from 20% to 70% in each case, and 17.9% to 50% in each primer. Serum HBV infection, tumor size,histological grade, tumor capsule, as well as tumor intrahepatic metastasis, might be correlated with genetic alterations on certain primers. A band with a higher intensity of 480 bp or so amplified fragments in tumor DNA relative to normal DNA could be seen in 27 of 56 tumor samples using primer 4. Sequence analysis of these fragments showed 91% homology with Homo sapiens double homeobox protein DUX10 gene.CONCLUSION: Genetic alterations are a frequent event in HCC, and tumor related DNA fragments have been found in this study, which may be associated with hepatocarcinogenesis. RAPD is an effective method for the identification and analysis of genetic alterations in HCC, and may provide new information for further evaluating the molecular mechanism of hepatocarcinogenesis.

Direct cloning and transplanting of large DNA fragments from Escherichia coli chromosome

We applied a resistance split-fusion strategy to increase the in vivo direct cloning efficiency mediated by Red recombination. The cat cassette was divided into two parts： cma （which has a homologous sequence with cmb） and cmb, each of which has no resistance separately unless the two parts are fused together. The crab sequence was integrated into one flank of a target clon- ing region in the chromosome, and a linear vector containing the cma sequence was electroporated into the cells to directly capture the target region. Based on this strategy, we successfully cloned an approximately 48 kb DNA fragment from the E. coli DH1-Z chromosome with a positive frequency of approximately 80%. Combined with double-strand breakage-stimulated homologous recombination, we applied this strategy to successfully replace the corresponding region of the E. coli DH36 chromosome and knock out four non-essential genomic regions in one step. This strategy could provide a powerful tool for the heterologous expression of microbial natural product biosynthetic pathways for genome assembly and for the functional study of DNA sequences dozens of kilobases in length.

The Cloning and Expression of Renalase and the Preparation of Its Monoclonal Antibody

To obtain the recombination protein of renalase and prepare the monoclonal antibody, the human renalase gene was amplified from human kidney by specific primer and cloned the DNA fragments into the pET22b. After verification of the positive clones, the gene was transformed to E. coli BL21 to express the protein with 6His on C terminal. The Balb/c mouse was immunized with the purified protein to prepare the monoclonal antibody by hybidoma technique. The renalase protein was reconstructed and 2 strains of the hybidoma which can stable secrete renalase were obtained. The monoclonal antibody can both react with the both recombinant and human serum renalase.