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Slides preparation. - e.g., gelatin or poly – lysine treatment of slides siliconization of coverslips by precipitation ( e.g., ethanol) by cross-linkage (e.g., formaldehyde). probe. a) Choice of the probe - ds : DN0A , cDNA - ss : RNA , oligonucleotide ss-DNA
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Slides preparation - e.g., gelatin or poly – lysine treatment of slides • siliconization of coverslips • by precipitation ( e.g., ethanol) • by cross-linkage (e.g., formaldehyde)
probe a) Choice of the probe - ds : DN0A , cDNA - ss : RNA , oligonucleotide ss-DNA b) Preparation of the probe - DNA : fragment isolation (optional) - cDNA : cloning - RNA : cloning in transcription vectors - oligonucleotides c) Labeling of the probe - ds DNA : random primed DNA labeling nick translation , PCR - RNA : in vitro transcription , RT- PCR - oligonucleotides : endlabeling or tailing
Oligonucleotide 3’ –end labeling with DIG-ddutp , Biotin-ddUTP ,or Fluorescein-ddUTP
PCR DIG labeling reaction for highly labeled probes containing unique sequences
Oligonucleotide 5’ –end labeling with DIG-ddutp , Biotin-ddUTP ,or Fluorescein-ddUTP
A PCR Strategy for Rapid Generation of Template DNA for Synthesis of Labeled RNA probes
Consensus Promoter Sequences . The +1base is the first base incorporated into RNA during transcription .The underline indicates the minimum sequence required for efficient transcription
RNA labeling by in vitro transcription of DNA with DIG , Biotin or Fluorescein RNA Labeling Mix
Estimating the yield in a spot test with a DIG-labeled control
Specimen pretreatment • Treatments to prevent background staining - endogenous enzyme inactivation - RNase-treatment • Permeabilization - diluted acids - detergent/alcohol - proteases
Determination of hybridization conditions, e.g., • determination of hybridization temperature , pH ,use of formamide , salt concentration • composition of hybridzation solution • Probe concentration
Prehybridization Incubation of specimen with a pre-hybridization solution (= hybridization solution minus probe) is performed at the same temperature as hybridization • denaturation of probe and target • pH or heat • simultaneous or separate denaturation of probe and target ( if double stranded
Hybridization Components of the solution are mainly : • Denhardt’s Mix ( Ficoll, BSA, PVP) • heterologous nucleic (e.g., herring sperm DNA / tRNA / competitor) • sodium phosphate, EDTA, SDS, salt • formamide • dextran sulfate
post-hybridization steps • treatment with single strand specific nuclease(optional) • strigency washes
Detection - blocking step - antibody incubation - colorimetric substrate for fluorescence microscopy - counterstaining - mounting
In situ hybridization of H19 rat probe to Mouse embryo using Anti sense probe
In situ hybridization of H19 rat probe to Mouse embryo using sense probe
Hepator cellular carcinoma stained with H19 and alpher-pheto-protien.
Tcc at different cancer grades with increasing expression of H19 gene
Standard carne with increasing probe concentration at the same slide