The pGEM-T is 3kb in length, and contains the amplicin resistance gene, conferring selection of the plasmid in E. coli, and the ori site which is the bacterial origin of replication. The plasmid has multiple cloning sites as shown below. The coding sequence was inserted by TA cloning. Many E. coli strains are suitable for the propagation of this vector including JM109, DH5α and TOP10.
The coding sequence can be easily obtained by digesting the vector with proper restriction enzyme(s). The coding sequence can also be amplified by PCR with M13 primers, or primer pair SP6 and T7.
The influenza viral Hemagglutinin (HA) protein is a homo trimer with a receptor binding pocket on the globular head of each monomer.HA has at least 18 different antigens. These subtypes are named H1 through H18.HA has two functions. Firstly, it allows the recognition of target vertebrate cells, accomplished through the binding to these cells' sialic acid-containing receptors. Secondly, once bound it facilitates the entry of the viral genome into the target cells by causing the fusion of host endosomal membrane with the viral membrane.The influenza virus Hemagglutinin (HA) protein is translated in cells as a single protein, HA0, or hemagglutinin precursor protein. For viral activation, hemagglutinin precursor protein (HA0) must be cleaved by a trypsin-like serine endoprotease at a specific site, normally coded for by a single basic amino acid (usually arginine) between the HA1 and HA2 domains of the protein. After cleavage, the two disulfide-bonded protein domains produce the mature form of the protein subunits as a prerequisite for the conformational change necessary for fusion and hence viral infectivity.