ABSTRACT
Human IL-6,IL-10,IL-13 and SCF cDNAs encoding extra - cellular domain were isolated by reverse transcription polymerase reaction (RT-PCR). These cDNA fragments were inserted into expression vector PBV220 which contains PRP_(L), promoters and SD sequence. Then the E. coli DH5? were tronsformed with the recombinant plasmids. After screening, the clones carrying those recombinant plasmids were identified. SDS-PAEG and biological assay indicated that human IL-6, IL-10 and IL-13 were expressed in E.coli. The expression level of rhIL-6 was as high as 30% of the total bacterial protein.
ABSTRACT
A chemical method to prepare biotin-labeled nucleic acid probe for nonisotopic hybridization is introduced. The method involves the bisulfite-catalyzed transamination reaction of cytosine residues in nucleic acids with ethylenediamine or hexanediamine. Primary amino groups on the cytosine derivatives are then reacted with biotiny-N-hydroxysuccinimide ester. Results of dot blot and Southern blot carried out with biotinlabeled ? DNA probe show that such nonisotopic probe method is sensitive, specific, repeatable and unexpensive.
ABSTRACT
The conditions for denaturation of DNA and RNA were invertigated. The results show that one minute to heat DNA at 100鈩?is sufficient for denaturation of DNA (several hundreds bp to 23kb). DNA degraded more obviously with longer neating time and the degradation decreased when DNA was dissdved in TE buffer. But no difference of degree of RNA degradation was found in there three conditions for RNA denaturation.