ENU mutagenesis and the Kyoto University Rat Mutant Archive (KURMA)

The ENU mutagenesis project is not part of NBRP-Rat. However, for scientific reasons and the need for genetically modified rat models that resemble allelic variations in humans and in so far resemble human patients, the Kyoto University Rat Mutant Archive (KURMA) was integrated into NBRP rat and provides interesting models for various fields in biomedical research.

An ENU-induced mutant archive for gene targeting in rats.
Mashimo T. et al. Nat Genet. 2008 May;40(5):514-5.

The priciple workflow of the ENU program is shown in the picture below:

ENU scheme
ENU is injected intraperitoneally using a split dose of 2 x 40 mg/kg into 9 and 10 weeks old male F344/NSlc rats. These males are mated 10 weeks after the second ENU injection. DNA and sperm of their offspring (G1) are stored at the Kyoto University Rat Mutant Archive (KURMA). The screening technique MuT-POWER can be applied to the DNA of the archive at any given time in the future and in case of successful mutation detection, intracytoplasmic sperm injection (ICSI) is used to derive viable offspring from the G1 sperms.
Preliminary results suggests that the mutation rate of KURMA is 1 per 3.7 MBp. The current number of G1 animals is 5,000; 10,000 G1 animals will be obtained in the future. An excerpt of some mutant genes with successful screening outcome is listed below.

Examples of successfully obtained mutations in targeted genes

Gene symbol

Gene name

Genbank

G1 number

Base mutation

AA change

Type

SIFT predictiona

Chrnb2

cholinergic receptor, nicotinic, beta polypeptide 2

NM_019297

Kyo2146

G -> C

-

Intronic

-

Clcn2

chloride channel 2

NM_004366

Kyo0013

C108A

-

Silence

-

Gabra1

gamma-aminobutyric acid A receptor, alpha 1

NM_183326

Kyo0760

A369T

-

Silence

-

Gabra1

gamma-aminobutyric acid A receptor, alpha 1

NM_183326

Kyo1358

C1175G

A392V

Missense

Intolerant

Gabrg2

gamma-aminobutyric acid A receptor, gamma 2

NM_012957

Kyo0570

A1041T

-

Silence

-

Scn1a

sodium channel, voltage-gated, type I, alpha

NM_030875

Kyo0631

A1616C

E539A

Missense

Tolerant

Scn1a

sodium channel, voltage-gated, type I, alpha

NM_030875

Kyo0811

A4246C

N1417H

Missense

Intolerant

Scn1b

sodium channel, voltage-gated, type I, beta

NM_017288

Kyo1866

T -> C

-

Intronic

-

Scn2a

sodium channel, voltage-gated, type II, alpha

NM_021007

Kyo0450

T-20A

-

5'UTR

-

Scn2a

sodium channel, voltage-gated, type II, alpha

NM_021007

Kyo0292

T -> A

-

Intronic

-

aPotential effect of a mutation on the corresponding protein was predicted as tolerant or intolerant by SIFT analysis.