Transfer Membranes

Protocol 7: Colony Hybridizations and Plaque Lifts with Nylon Membranes
with Pure Nylon Neutral and Reprobe Nylon Positively Charged Transfer Membranes.
Membrane Preparation
If necessary, sterilize the membrane between two pieces of filter paper in the autoclave for 15 minutes. Allow the membrane
to wet on the agar surface (or appropriate medium) on the petri dish. Mark the membrane so that future orientation is
assured.
Colony Transfer
Step 1:
Incubate cell colonies and plaques at 37°C until they are 0.5 – 1.0 mm in diameter. Alternatively, the cell colonies may be
grown after the membrane and appropriate cell media have been added to the plate.
Step 2:
Replication. With forceps, lift the membrane from the surface of the plate and place it colony/plaque side up on two sheets
of dry filter paper. Carefully place a fresh membrane over the one with the colonies, and apply gentle pressure with a
replication tool or glass plate. Avoid smearing the colonies when separating the membranes. To amplify plasmids, transfer
the membrane to an agar plate with 200 – 250 µg/ml of chloramphenicol at 37°C for 10 hours.
Plaque Transfer
Step 1:
Cells should be plated with phage in soft agarose and incubated at 37°C until plaques are 0.2 mm. After incubation, chill
plate at 4°C for 15 minutes to set the agarose.
Step 2:
Place membrane on the plate in complete contact with the agarose and assure orientation by marking. Allow phage to
transfer for 2 minutes. Increase the transfer time if many transfers are to be performed.
Isolation
Lay membrane on filter paper prewet with 0.5 N NaOH (add 1.5 M NaCl for plaques) for 5 – 7 minutes to denature the
nucleic acid.
Immobilization Colonies
Bake at 80°C until dry or UV crosslink per manufacturer's instructions. Neutralize the membrane on filter paper saturated
with 1 M Tris · HCl (pH 8.0) for 5 minutes. Incubate on filter paper saturated with 1 M Tris · HCl (pH 8.0), 1.5 M NaCl for
5 minutes. Wash in 2X SSC. Bake membranes for 15 – 30 minutes until dry at 80°C.
Plaques
Neutralize and incubate the membrane on filter paper saturated with 0.5 M Tris · HCl (pH 8.0), 1.5 M NaCl. Place the
membrane on sheets wet with 2X SSC and blot dry. Bake membranes until dry for 15 – 30 minutes at 80°C.
Hybridization
Use 5 – 10 ml of prehybridization buffer solution per membrane, with gentle agitation. Prehybridize for 1 hour in a heatsealable
bag.
Prehybridization Buffer
50 % Formamide
1 – 3X Denhardt’s solution
5X SSPE
0.1 – 0.5 % SDS
100 – 200 µg/ml denatured DNA*
Hybridize in freshly made prehybridization buffer with 1 – 5 x 10 6 cpm/ml probe, or approximately 5 – 20 ng/ml. Incubate
for 12 – 20 hours at 45°C.
* Denatured DNA is typically Salmon Sperm DNA, phenol/chloroform extracted, sheared, and heat denatured.
Detection
Autoradiograph on X-ray film at -70°C for 48 hours or more.
Probe Removal (Stripping)
See probe removal details in the appropriate sections of this protocol please see Protocol 1.
07
protocols
protocol
© 2008 AppliChem • Transfer Membranes 29