DISTAMYCIN A PLUS DAPI FLUORESCENT STAINING (Dst/DAPI)
In man, this technique produces brilliant fluorescence at the C-blocks of chromosomes 1, 9, and 16, at the heterochromatic part of the Y, and at a short arm segment of chromosome 15 (15pll).
1.. McIlvaine citric acid-Na2KP04 buffer, pH 7.0 (buffer A)
2. Distamycin A-HCl (Boehringer; Serva; Sigma) 0.2 mg/ml of
3. DAPl (4' - 6-Diamidino-2-phenylindole-2HCl') (Serva)
Stock solution: 0.2 mg/ml of distilled water.
Staining solutions: 0.2 - 0.4 µg/ml of buffer A
1. Flood slide with Dst-solution, cover with coverslip and
incubate at room temp. for 5-15 mins.
2. Remove coverslip and rinse briefly with buffer, pH 7.0
3. Flood with DAPI solution, cover with coverslip and
incubate in the dark at room temp. for 5-15 mins.
4. Rinse briefly with buffer A.
5. Mount in buffer A, remove excess buffer by blotting over
coverslip. Seal with rubber solution.
excitation: approximately 360 nm
emission: approximately 460 nm
- Distamycin A tends to lack stability in aqueous solution unless
- DAPI stock solution may be kept in the refrigerator for several
weeks without detectable deterioration or stored frozen.
- the stained preparations may exhibit rapid fading when first
examined but usually stabilize after a day or so stored at 4'C
Schweizer, D..Ambros, P. and Andrle, M.: Modification of DAPI
banding on human chromosomes by prestaining with a DNA-binding oligopeptide antibiotic, distamycin A
Experimental Cell Research III, 327-332 (1978).