culturing a host transformed by {HEAD ~ a vector} comprising a DNA segment having {TAIL ~ the following nucleotide sequence}: 
culturing a host transformed by { HEAD ~ a vector } comprising a DNA segment having { TAIL ~ the following nucleotide sequence } :
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH