Biomedical subjects

Zhi-Hu Zhao

Publications and source records attributed to Zhi-Hu Zhao.

4 recordsLinked to original sources

PubMed2004

[Functional expression of DNA binding domain of Zif268 in Escherichia coli].

As the ubiquitous nucleic acids recognizing motif, Zinc finger protein play important role in regulation of gene expression. The study of recognization specific will greatly facilitate understanding the delicate interaction of Zinc finger protein and DNA. By the choice of expression vector, the induction and culture conditions, the DNA binding domain of Zif268 was expressed in Escherichia coli partly solubly. The gel mobility shift assay shows that purified DNA binding domain can bind its natural target sequence specifically, which indicates the DNA binding domain remains its DNA binding activity in Escherichia coli. The functional expression of DNA binding domain of Zif268 will greatly facilitate the development of in vivo genetic selection assay for the study of Zinc fingers-DNA interaction.

DNA-Binding Proteins↗

PubMed2003

[Study on relationship between length of homologous sequences and chromosomic recombination rate in Saccharopolyspora erythraea].

In order to study the relationship between lengths of homologous fragments and chromsomic recombination rate in Saccharopolyspora erythraea, three homologous sequences, with mutant loci and different flanking sequences, (26bp + 27bp), (500bp + 576bp) and (1908bp + 1749bp), were synthesized by chemical reaction or PCR amplification, and cloned into pWHM3 to construct homologous recombination plasmids, pWHM1113, pWHM1116 and pWHM1119. When the plasmids were transformed into protoplast of Saccharopolyspora erythraea A226 under PEG mediated, on an average 30, 69 and 170 transformants grew on each plate for the three plasmids respectively, but chromosomic integration frequency were 0, 2% and 19% among corresponding transformants. Both pWHM1116 and pWHM1119 could take double crossover recombination, and exchange the mutant loci in the chromosome. It was concluded that when the flanking sequences were equal or more than (500bp + 576bp), they could take effective single and double recombination with Saccharopolyspora erythraea chromosome.

Chromosomes, Bacterial↗

PubMed2003

[Study of recombinant stem cell factor].

Stem cell factor is an important hematopoietic growth factor. In this study, the human stem cell factor was produced by recombinant E. coli, and the structure and biological activity of the recombinant stem cell factor(rhSCF) was studied. It was indicated that the rhSCF was a uncovalent dimer in phosphate buffer,and had the correct mass spectra, mass peptides spectra, composition of amino acid, N-terminal sequernce, C-terminal sequence and intrachain disulfide linkages, rhSCF alone or synergy with rhG-CSF could mobilze hematopoietic progenitors to blood in monkey.

Animals↗

PubMed2002

[Construction of Saccharopolyspora erythraea M synthesizing a novel ketolide 3-deoxy-3-oxo-erythronolide B].

Genetic engineering on macrolide antibiotics was a new field in recent years and more than 100 novel polyketides had been produced until then. Using genomic DNA of S. erythraea A226 as a template, about 3.2 kb DNA fragment without KR6 domain was amplified by overlapping PCR technique and cloned into pWHM3 carrier, which resulted in the construction of homologous recombinant plasmid pWHM2201. Plasmid pWHM2201 was introduced into protoplasts of S. erythraea A226 by PEG-mediated transformation and integrated into the gene locus for erythromycin biosynthesis. After integrants grew for two generations on R3M media without Tsr, they were protoplasted and grown on R3M plates. By PCR identification, 8 mutants without KR6 domain were selected out and named S. erythraea M(1-8). With the identification of mass spectrometry, it was proved that S. erythraea M1 synthesized a novel ketolide compound 3-deoxy-3-oxo-erythronolide B.

Anti-Bacterial Agents↗