The invention also relates to {HEAD ~ DNA constructs} encoding {TAIL ~ the variants}, and to vectors and cells harboring the DNA constructs 
The invention also relates to { HEAD ~ DNA constructs } encoding { TAIL ~ the variants } , and to vectors and cells harboring the DNA constructs
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH