(1) The corresponding RNA was isolated from hepatocytes, endostatin gene was obtained by reverse transcription (or reverse transcription), and then amplified in vitro by PCR technology to obtain more target genes.

(2) After double enzyme digestion, the sticky ends of the target gene are different, and the sticky ends of the cutting vector are also different, which can avoid the reverse connection between the target gene and the vector, reduce the connection between the target gene and the target gene, and improve the proportion of recombinant plasmid.

(3) LacZ gene of E.coli pUC 18 plasmid can express β -galactosidase if foreign gene is not inserted. When the medium contains IPTG and Xgal, Xgal will be hydrolyzed to blue by β galactosidase, and E.coli will form blue colonies. White colony formation. In addition to glucose, nitrogen sources, inorganic salts, water, growth factors and other essential nutrients for Escherichia coli, IPTG, X-gal and ampicillin should also be added to the selected medium. Because the target gene was inserted into the LacZ gene of the recombinant plasmid, the LacZ gene could not express β-galactosidase, so the Escherichia coli successfully introduced into the recombinant plasmid formed a white colony in the culture medium.

(4) According to the data in the table, the higher the concentration of crude expression product, the less the number of surviving endothelial cells, indicating that recombinant endostatin (or crude expression product) can inhibit the proliferation of capillary endothelial cells.

So the answer is: (1) reverse transcription PCR? (2) Reverse

(3) (3) LacZ gene on white recombinant plasmids of IPTG, X-gal and ampicillin has been destroyed and cannot be expressed.

(4) Living cell count, endostatin can effectively inhibit vascular proliferation.