280
JAIME GOSALVEZ et al.
Fig. 3. a-f/a'- f' Selected chromosomes accompanied by a pseudo-3D intensity profile (prime figures) from Chinese
hamster Don cells (a-c/a'- c') and human lymphocytes (d-f/d' - f) hybridised with a telomeric probe after "in situ"
digestion with nucleases. ala' Selected chromosome from a Chinese hamster cell digested with AluI alone (control).
bIb' Selected chromosome from a Chinese hamster cell digested with AluI+ExoIII. clc' Selected chromosome from a
Chinese hamster cell digested with AluI + Bal3 I. ExoIII shows high enzymatic activity; produces a large amount ofssDNA
in interstitial telomere-like sequence areas of Chinese hamster chromosomes, yielding a strong hybridisation signal.
Bal3I shows a low enzymatic activity; removes little of the dsDNA, so after heat denaturation, the amount of target
susceptible to being hybridised is only very slightly reduced and the FISH signal is very strong and closer to that of its
control. dId' Selected chromosome from a human lymphocyte digested with AluI (control). e/e' Selected chromosome
from a human lymphocyte digested with AluI +ExoIII. flf' Selected chromosome from a human lymphocyte digested with
AluI+Ba131. ExoIII has low enzymatic activity; produces a reduced amount ofssDNA in terminal telomeric sequences of
JAIME GOSALVEZ et al.
Fig. 3. a-f/a'- f' Selected chromosomes accompanied by a pseudo-3D intensity profile (prime figures) from Chinese
hamster Don cells (a-c/a'- c') and human lymphocytes (d-f/d' - f) hybridised with a telomeric probe after "in situ"
digestion with nucleases. ala' Selected chromosome from a Chinese hamster cell digested with AluI alone (control).
bIb' Selected chromosome from a Chinese hamster cell digested with AluI+ExoIII. clc' Selected chromosome from a
Chinese hamster cell digested with AluI + Bal3 I. ExoIII shows high enzymatic activity; produces a large amount ofssDNA
in interstitial telomere-like sequence areas of Chinese hamster chromosomes, yielding a strong hybridisation signal.
Bal3I shows a low enzymatic activity; removes little of the dsDNA, so after heat denaturation, the amount of target
susceptible to being hybridised is only very slightly reduced and the FISH signal is very strong and closer to that of its
control. dId' Selected chromosome from a human lymphocyte digested with AluI (control). e/e' Selected chromosome
from a human lymphocyte digested with AluI +ExoIII. flf' Selected chromosome from a human lymphocyte digested with
AluI+Ba131. ExoIII has low enzymatic activity; produces a reduced amount ofssDNA in terminal telomeric sequences of