# US 9,040,235 B2 · Method for sequencing RNA by in-source decay using matrix assisted laser desorption ionization time of flight mass spectrometer

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- Number: US 9,040,235 B2
- Document ID: US9040235B2
- Status: Granted
- Kind: B2
- Application number: 13/215,029
- Filed: 2011-08-22
- Published: 2012-04-05
- Granted: 2015-05-26
- Earliest claimed: 2010-08-31
- Assignees: Shimadzu Corporation
- Applicants: Masaki Yamada
- Inventors: Masaki Yamada
- Web page: https://patentgrep.com/patent/US9040235B2

## CPC

- C12Q 1/6872: involving mass spectrometry
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES

## Abstract

An analytic method is provided for obtaining much sequence information by causing in-source decay of modified RNA and non-modified RNA and generating many fragment ions. Particularly, a method for analysis wherein a matrix that efficiently causes decomposition by in-source decay of RNA of 20 bases or longer is used in an apparatus that has a laser of a wavelength commonly used in MALDI-TOF MS. A specimen containing RNA is subjected to matrix assisted laser desorption ionization time of flight mass spectrometry that uses 2,4-dihydroxyacetophenone as a matrix to obtain fragment ions derived from the RNA. The difference in mass between the peaks of ions in the fragment ions is used to analyze the sequence of the RNA.

## Claims

### Claim 1

A method for sequencing RNA, comprising:
subjecting a specimen containing RNA to matrix assisted laser desorption ionization time of flight mass spectroscopy using 2,4-dihydroxyacetophenone as a matrix to obtain fragment ions derived from said RNA by in-source decay; and
analyzing said RNA sequence by the difference in mass between peaks of said fragment ions.

### Claim 2 (depends on 1)

The method for RNA sequencing according to claim 1 wherein said RNA has a 2′ modified group in the ribose.

### Claim 3 (depends on 2)

The method for RNA sequencing according to claim 2 wherein said RNA has a 2′—O-methyl group in the ribose.

### Claim 4 (depends on 1)

The method for RNA sequencing according to claim 1, wherein said RNA has a length of between 20 and 30 bases.