Y. Fujibayashi et al., A novel In-111-labeled antisense DNA probe with multi-chelating sites (MCSprobe) showing high specific radioactivity and labeling efficiency, NUCL MED BI, 26(1), 1999, pp. 17-21
A multi-aminolinked oligodeoxynucleotide (ODN) was synthesized by substitut
ion of dT with aminolinked dU in the sequence, following conjugation with i
sothiocyanobenzyl-EDTA (IBE) for In-111 labeling. As a model target gene, t
he c-erbB-2 protooncogene was used. The probability of the number of aminol
inked dU in the 20mer ODN was 5, but there were actually 3 and 4 in the sel
ected antisense and sense ODNs, respectively. The IBE/ODN conjugation level
s of probes with multi chelating sites (MCS-probe) were 1.6 (antisense) and
2.4 (sense), more than 50 times higher than those of our previous studies
using 5'-end aminolinked ODNs (IBE/ODN = 0.03), Labeling studies using the
MCS probe and In-111 indicated that specific radioactivity as high as 48 MB
q/nmol could be obtained with a labeling efficiency of over 90%. The In-111
antisense MCS-probe could bound to sense ODN under physiological condition
s, but the In-111-sense-MCA-probe could not. Thus, side-chain modification
of ODN for metal labeling is considered to be useful for antisense techniqu
es. NUCL MED BIOL 26;1:17-21, 1999. (C) 1998 Elsevier Science Inc.