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Direct Disease Diagnosis
by DNA computing
2004.2.10
임희웅
Profiling
DNA
Diagnosis
Yes
or
No
RNA
Protein
DNA Computing
Micro-array vs. DNAC
Sample tissue
Reference
mRNAs
cDNA/Tagging
Hyb with probes
Probe design
with NACST
Hyb in array
Digestion with S1
or bead separation
Preparation of
input molecules
Scanning
Molecular algorithm
Statistical processing
Readout
Micro-array 진단칩
DNAC 진단칩
Sample
환자 RNA
환자 RNA
Instruments
분자생물학 실험장비
(항온기, 원심분리기 등)
Scanner
Computer
Time
1~2 day
<1 day, ~hours
Human
intervention
Yes
No
?
Objective

Diagnosis of disease




Target disease: Lung cancer
Transcribed mRNAs in the region of interest
Target gene: As less as possible, 2~3 genes or more
Simplify the diagnosis process: Yes/No problem
추진전략
디지탈지노믹스
위탁 연구 기관
폐암과 정상 폐조직
샘플의 microarray 분석
Model case에 대한
DNA computing 방법 개발
폐암 진단을 위한
표지 유전자 선별
진단용 DNA computing을
위한 알고리즘 구축
DNA computing에 의한
폐암 진단 방법 구현
1차년도
2차년도
3차년도
폐암 진단 DNA computing
chip 시제품 개발
Formulation Model
x3
Expression level
(concentration)
x1
x1t1  x2t2  x3t3  0
x2
(+)
(-)
Gene1: x1
Gene2: x2
Weighted sum
Gene3: x3
sum  x1t1  x2t2  x3t3
Classification
with threshold 0
yes
no
t1, t2, t3 are predetermined constants from training samples
sum
Implementation
: Profiling and Classification with DNAC

How to implement…

Implementation of weighted sum by t-value




Positive/Negative weight
Multiplication and summation
Classification by threshold value
Method
Preprocessing and
Input data generation
Analysis and
Classification
Preprocessing and
Input Data Generation
RNA1
RNA1
RNA1
RNA2
RNA2
RNA3
RNA4
Expressed RNA
Probe1
Probe1
Probe1
Probe1
+
hybridization
Probe2
Probe2
Probe2
Probe2
Probe3
Probe3
Probe3
Probe3
Probes
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA2
RNA2
Probe2
Probe2
RNA2
RNA2
Probe2
Probe2
S1
exonuclease
RNA3
Probe3
RNA3
Probe3
RNA4
Probe1
Probe2
Probe2
Probe3
Probe3
Probe3
Hybridization Product
•Input generation for Computing
•Expression level  concentration
DNAC Algorithm

Basic Framework


Preprocessing by hybridization of probes and expressed RNAs.
Detailed algorithm is determined by probe (DNA, PNA, molecular
beacon) and modification.


Weight  probe, modification
Weight Encoding



SYBR
CyX-nucleotide
Molecular beacon
SYBR

SYBR


Intercalating dye (cf. ETBR)
Method

Hybridization  digestion  separation  signal comparison

Separation: charge difference of DNA vs. PNA
Hybridization between total
RNA and DNA or PNA
t-value의 부호에 따라서 probe를 DNA 혹은
PNA로 만들어서 hybridization
Digestion of ssRNA region
Exonuclease treatment
Electrophoresis and staining
Readout by scanning
Staining with intercalating dye
Decision by relative amount
CyX-nucleotide

Weight encoding



Dye modification ratio in probe proportional to weight value
Sign of weight: Red vs. Green
Method

Hybridization elimination of unbound probe Read out
Hybridization between total
RNA and modified probes
Elimination of unbound probes
Readout by fluorometer
Modified probes: amine기를 이용한
Column separation
PCR clean-up kit
Hybridization by modified complementary strands
Fluorescence intensity로부터 decision
Molecular Beacon

Weight encoding



Sign  red/green dye in Molecular Beacon
Weight value  # of Molecular Beacon per mRNA
Pros and Cons



Need no separation
Need no digestion
But, high cost.
Control
Tumor
Wavelength
Exonuclease
Normal
Mix
Wavelength
Normal
Molecular beacon
Tumor
Mixture
Wavelength
To do…

Preliminary experiment before Lung cancer



Real data from Digital Genomics Inc.
Real genes from Digital Genomics Inc. (Cell line)
Verification of classification model



Have to hide the gene names!
Etc



Verification of our method by wet-lab experiment in test tube
Notice!


Verification of weighted sum model by plotting real profile data
Consideration of the implementation on Lab-on-a-Chip
Other statistical method for diagnosis
Paper Title


Direct Disease Diagnosis by DNA Computing
Novel Molecular Algorithm for Disease Diagnosis
Old Slide

Detailed Method


Implementation of weighted sum and detection
With or without separation

With separation



Without separation


Separation: separation based on fluorescence, DNA/PNA probe
Comparison: Measurement of the signal that is proportional to the number
of nucleotides (like absorbance)
Detection by modification of every nucleotide?
Weight representation

Probe length



Execution of weighted sum by only the combination of hybridization and
S1 nuclease digestion (or bead separation)
Multiplication  counting the total nucleotides number
# of dye in probe



Molecular beacon
# of dye modification proportional to weight
Representation of (+)/(-): fluorescence
Separation Method I
Tag for
separation
(fluorophore)
RNA1
RNA1
RNA1
RNA2
RNA2
RNA3
RNA4
+
hybridization
Probe1
Probe1
Probe1
Probe1
Probe2
Probe2
Probe2
Probe2
Probe3
Probe3
Probe3
Probe3
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA2
RNA2
Probe2
Probe2
S1
RNA3
exonuclease
Probe3
RNA2
RNA2
Probe2
Probe2
RNA3
RNA4
Probe1
Probe2
Probe2
Probe3
Probe3
Probe3
Probe3
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA3
RNA2
RNA2
Probe2
Probe2
separation
Probe3
RNA3
Probe3
RNA2
RNA2
Probe2
Probe2
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA3
Probe3
RNA2
RNA2
Probe2
Probe2
Linear signal
amplification
w/o bias
Comparison of
nucleotides
amounts
Separation Method II
RNA1
RNA1
RNA1
RNA2
RNA2
RNA3
RNA4
Probe1
Probe1
Probe1
Probe1
+
hybridization
PNA
Probe2
Probe2
Probe2
Probe2
Probe3
Probe3
Probe3
Probe3
Blue block: DNA probe
Green block: PNA probe
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA2
RNA2
Probe2
Probe2
Exonuclease
RNA3
Probe3
RNA2
RNA2
Probe2
Probe2
RNA3
RNA4
Probe1
Probe2
Probe2
Probe3
Probe3
Probe3
Probe3
Group I
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA2
RNA2
Probe2
Probe2
RNA3
Separation
by charge
RNA3
Probe3
Group II
Probe3
∵ PNA has no charge, and therefore, nucleic
acids of group II will show less mobility than
those of group I
RNA2
RNA2
Probe2
Probe2
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA3
Probe3
RNA2
RNA2
Probe2
Probe2
Linear signal
amplification
w/o bias
Comparison of
nucleotides
amounts
Without Separation
RNA1
RNA1
RNA1
Probe1
Probe1
Probe1
RNA2
RNA2
Probe2
Probe2
RNA3
Probe3
(+)
(-)
Positive!
•If it is possible to modify every nucleotide in
probes…
•Modify every nucleotide in probe differently
along the sign of the weight.
•Diagnosis by observing the final signal of
preprocessed input data.
To do…

Verification of classification model



Verification of weighted sum model by plotting real profile
data
Other statistical method for diagnosis
Available experimental technique or new



Other amplification/detection methods
Signal amplification (up to detection limit)
Consideration of the implementation on Lab-on-a-Chip
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