Jg. Hacia et al., Design of modified oligodeoxyribonucleotide probes to detect telomere repeat sequences in FISH assays, NUCL ACID R, 27(20), 1999, pp. 4034-4039
A series of dye-labeled oligonucleotide probes containing base and sugar mo
difications were tested for the ability to detect telomeric repeat sequence
s in FISH assays. These modified oligonucleotides, all 18 nt in length, wer
e complementary to either the cytidine-rich (C(3)TA(2))(n) or guanosine-ric
h (T(2)AG(3))(n) telomere target sequences, Oligonucleotides were modified
to either increase target affinity by enhancing duplex stability [2'-OMe ri
bose sugars and 5-(1-propynyl)pyrimidine residues] or inhibit the formation
of inter- or intramolecular structures (7-deazaguanosine and 6-thioguanosi
ne residues), which might interfere with binding to the target. Several dye
-labeled oligonucleotide probes were found that could effectively stain the
telomeric repeat sequences of either cytidine- or guanosine-rich strands i
n a specific manner. Such probes could be used as an alternative to peptide
nucleic acids for investigating the dynamics of telomere length and mainte
nance. In principle, these relatively inexpensive and readily synthesized m
odified oligonucleotides could be used for other FISH-related assays.