All Phenotypes Mbnl2<em1Coop> MGI Mouse

Phenotypes associated with this allele

♀	phenotype observed in females
♂	phenotype observed in males
N	normal phenotype

digestive/alimentary system

abnormal intestinal smooth muscle morphology ( J:386516 )

• mice treated with tamoxifen between 25 and 40 days of age for a total of 8 days and a minimum of 4-week washout period exhibit thickened smooth muscle layers in the intestine

• however, no histopatholgical changes are seen in the intestine, with no infiltration of inflammatory cells or atrophy of villi in TAM treated mice

• Ccnd1, but not Pcna, is upregulated in TAM treated mice, suggesting that smooth muscle cells may enter but not progress through the cell cycle or could indicate cellular senescence

decreased intestine length ( J:386516 )

• whole intestines are shorter in TAM treated mice

decreased small intestine length ( J:386516 )

• small intestine length is shorter while colon length is unaffected in TAM treated mice

increased intestinal transit time ( J:386516 )

• mice treated with tamoxifen exhibit a delay in both small intestine and colonic transit

abnormal intestine physiology ( J:386516 )

• jejunum segments from TAM-treated mice show increased force generation in response to carbachol, indicating a strong response and decreased ability to normalize tone after carbachol stimulation

• colonic segments from TAM-treated mice show increased baseline tone which is concurrent with decreased contractile frequency, increased contractile amplitude, and increased contractile activity

• colonic segments from TAM-treated mice show decreased contractile force after high doses of carbachol stimulation

muscle

abnormal intestinal smooth muscle morphology ( J:386516 )

• mice treated with tamoxifen between 25 and 40 days of age for a total of 8 days and a minimum of 4-week washout period exhibit thickened smooth muscle layers in the intestine

• however, no histopatholgical changes are seen in the intestine, with no infiltration of inflammatory cells or atrophy of villi in TAM treated mice

• Ccnd1, but not Pcna, is upregulated in TAM treated mice, suggesting that smooth muscle cells may enter but not progress through the cell cycle or could indicate cellular senescence

abnormal muscle physiology ( J:386516 )

• TAM treated mice show increased smooth muscle contractile tone of jejunum and colon segments ex vivo

abnormal muscle contractility ( J:386516 )

• smooth muscle contraction dynamics are disrupted to favor a hypercontracted state in both the jejunum and colon

abnormal muscle tone ( J:386516 )

• TAM treated mice exhibit increased jejunum and colon smooth muscle tone

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
myotonic dystrophy type 1		DOID:11722	OMIM:160900	J:386516

Allelic Composition	Mbnl1^em1Coop/Mbnl1^em1Coop Mbnl2^em1Coop/Mbnl2^em1.1Coop X/Tg(Myh11-icre/ERT2)1Soff
Genetic Background	Not Specified

Find Mice

Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Mbnl1^em1Coop mutation (0 available); any Mbnl1 mutation (39 available)
Mbnl2^em1.1Coop mutation (0 available); any Mbnl2 mutation (65 available)
Mbnl2^em1Coop mutation (0 available); any Mbnl2 mutation (65 available)
Tg(Myh11-icre/ERT2)1Soff mutation (2 available)

♀	phenotype observed in females
♂	phenotype observed in males
N	normal phenotype

digestive/alimentary system

abnormal intestinal smooth muscle morphology ( J:386516 )

• intestine of mice treated with tamoxifen between 25 and 40 days of age for a total of 8 days and a minimum of 4-week washout period exhibits thickened smooth muscle layers; an increase in both circular and longitudinal jejunum smooth muscle thickness and in longitudinal colonic muscle thickness are seen

• however, no histopatholgical changes are seen in the intestine, with no infiltration of inflammatory cells or atrophy of villi and cell size in TAM treated mice

• structure of smooth muscle appears normal in TAM treated mice suggesting that hypertrophy is not causative of the muscle thickening and markers of smooth muscle phenotypic modulation do not indicate cell dedifferentiation

• Ccnd1, but not Pcna, is upregulated in TAM treated mice, suggesting that smooth muscle cells may enter but not progress through the cell cycle or could indicate cellular senescence

decreased intestine length ( J:386516 )

• whole intestines are shorter in TAM treated mice

decreased small intestine length ( J:386516 )

• small intestine length is shorter while colon length is unaffected in TAM treated mice

increased intestinal transit time ( J:386516 )

• mice treated with tamoxifen exhibit a delay in both small intestine and colonic transit

growth/size/body

increased body weight ( J:386516 )

• small weight increase and no change in body length is seen 2 months after TAM treatment

muscle

abnormal intestinal smooth muscle morphology ( J:386516 )

• however, no histopatholgical changes are seen in the intestine, with no infiltration of inflammatory cells or atrophy of villi and cell size in TAM treated mice

• Ccnd1, but not Pcna, is upregulated in TAM treated mice, suggesting that smooth muscle cells may enter but not progress through the cell cycle or could indicate cellular senescence

Contributing Projects: Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
Citing These Resources Funding Information Warranty Disclaimer, Privacy Notice, Licensing, & Copyright Send questions and comments to User Support.	last database update 06/09/2026 MGI 6.24