Phenotypic Mutation 'Sinuous' (pdf version)
AlleleSinuous
Mutation Type missense
Chromosome11
Coordinate99,213,456 bp (GRCm39)
Base Change A ⇒ G (forward strand)
Gene Krt25
Gene Name keratin 25
Synonym(s) 4631426H08Rik, mIRSa1
Chromosomal Location 99,206,342-99,213,777 bp (-) (GRCm39)
MGI Phenotype FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a member of the type I (acidic) keratin family, which belongs to the superfamily of intermediate filament (IF) proteins. Keratins are heteropolymeric structural proteins which form the intermediate filament. These filaments, along with actin microfilaments and microtubules, compose the cytoskeleton of epithelial cells. The type I keratin genes are clustered in a region of chromosome 17q12-q21. [provided by RefSeq, Jul 2009]
PHENOTYPE: Mutations in this gene have a defect in hair formation resulting in a wavy coat and curly vibrissae. Some alleles may compromise normal growth. [provided by MGI curators]
Accession Number

NCBI RefSeq: NM_133730; MGI: 1918060

MappedYes 
Amino Acid Change Serine changed to Proline
Institutional SourceBeutler Lab
Gene Model not available
AlphaFold Q8VCW2
SMART Domains Protein: ENSMUSP00000048439
Gene: ENSMUSG00000035831
AA Change: S88P

DomainStartEndE-ValueType
low complexity region 2 12 N/A INTRINSIC
low complexity region 35 52 N/A INTRINSIC
Filament 74 389 4.13e-146 SMART
low complexity region 391 403 N/A INTRINSIC
Predicted Effect probably damaging

PolyPhen 2 Score 0.992 (Sensitivity: 0.70; Specificity: 0.97)
(Using ENSMUST00000038004)
Meta Mutation Damage Score Not available question?
Is this an essential gene? Probably nonessential (E-score: 0.090) question?
Phenotypic Category Autosomal Dominant
Candidate Explorer Status loading ...
Single pedigree
Linkage Analysis Data
Penetrance 100% 
Alleles Listed at MGI
All alleles(4) : Spontaneous(1) Chemically induced(3
Lab Alleles
AlleleSourceChrCoordTypePredicted EffectPPH Score
IGL01310:Krt25 APN 11 99208996 missense probably benign 0.28
IGL02415:Krt25 APN 11 99213398 missense probably damaging 1.00
IGL02816:Krt25 APN 11 99208977 missense probably benign 0.10
Plush UTSW 11 99213461 missense probably damaging 1.00
R0138:Krt25 UTSW 11 99213524 missense probably benign 0.00
R0219:Krt25 UTSW 11 99208885 missense probably benign 0.01
R0932:Krt25 UTSW 11 99212109 missense possibly damaging 0.94
R1733:Krt25 UTSW 11 99207378 nonsense probably null
R1855:Krt25 UTSW 11 99209141 missense probably damaging 1.00
R2120:Krt25 UTSW 11 99212023 missense probably benign 0.01
R2504:Krt25 UTSW 11 99208122 nonsense probably null
R3615:Krt25 UTSW 11 99208124 missense possibly damaging 0.64
R3616:Krt25 UTSW 11 99208124 missense possibly damaging 0.64
R4590:Krt25 UTSW 11 99208854 intron probably benign
R6250:Krt25 UTSW 11 99211989 missense probably damaging 1.00
R6331:Krt25 UTSW 11 99208253 missense probably damaging 1.00
R6927:Krt25 UTSW 11 99208205 missense probably damaging 1.00
R7067:Krt25 UTSW 11 99208209 missense probably benign 0.01
R7289:Krt25 UTSW 11 99212098 missense probably benign 0.15
R7360:Krt25 UTSW 11 99208232 missense probably benign 0.01
R8057:Krt25 UTSW 11 99208169 missense probably benign 0.44
R8090:Krt25 UTSW 11 99207416 critical splice acceptor site probably null
R8933:Krt25 UTSW 11 99212064 missense probably benign 0.31
R8995:Krt25 UTSW 11 99207382 missense probably benign
R9040:Krt25 UTSW 11 99207379 missense probably benign
Z1176:Krt25 UTSW 11 99213648 missense probably benign 0.44
Mode of Inheritance Autosomal Dominant
Local Stock Sperm, gDNA
Repository

none

Last Updated 2016-05-13 3:09 PM by Stephen Lyon
Record Created unknown
Record Posted 2008-08-07
Phenotypic Description
Sinuous was identified in N-ethyl-N-nitrosourea (ENU)-induced G1 mutant mice.  Sinuous heterozygotes animals have wavy fur up to weaning age (3 weeks old).  After weaning age, Sinuous animals appear normal.
Nature of Mutation
The Sinuous mutation was mapped to Chromosome 11, and corresponds to a T to C transition at position 312 of the Krt25 transcript, in exon 9 of 10 total exons.
 
297 AATGACCGCCTGGCCTCCTACCTGGACAACGTG
83  -N--D--R--L--A--S--Y--L--D--N--V-
 
The mutated nucleotide is indicated in red lettering, and causes a serine to proline substitution at residue 88 of the Keratin 25 protein.
Illustration of Mutations in
Gene & Protein
Protein Prediction
Figure 1. Keratin domain structure showing the α-helical domain, linker regions and head/tail domains. The Sinuous
mutation causes a proline to serine substitution at residue 88 of the Keratin 25 protein. This image is interactive.
Click on the image to view other mutations found in Krt25 (red). Click on the mutations for more specific information.   
The Sinuous mutation results in the substitution of a proline for a serine at amino acid 88 of keratin 25 (Figure 1).  It is unknown whether this protein is expressed and localized normally.
 
For additional information on Krt25, please see the record for Plush.
Putative Mechanism
The Sinuous mutation alters a well-conserved amino acid in the HIM of the K25 protein.  As this domain is critical for heterodimerization of keratin molecules, it is likely that the Sinuous mutation disrupts the proper formation of IF assembly resulting in the hair phenotypes seen in mutant animals.  The Sinuous mutation results in the substitution of a serine to a proline.  Proline residues are not typically found in the α-helical rod domains of normal keratin proteins, and they are known to destabilize α helices.  The presence of a proline at amino acid 88 is likely to disrupt the formation of the coiled-coils and the subsequent assembly of individual keratin subunits into IFs (1).
 
The amino acid altered in Sinuous mutants is close to the amino acid mutated in Plush mutant animals.  Sinuous mutants resemble Plush mutants, as well as the allelic classical wavy coat mutant Re (2), up until weaning age.  The mechanism for the phenotypic differences observed in Plush and Sinuous animals is unknown.
Primers Primers cannot be located by automatic search.
Genotyping
Sinuous genotyping is performed by amplifying the region containing the mutation using PCR, followed by sequencing of the amplified region to detect the single nucleotide change.  The primers used are the same used for Plush genotyping.
 
Primers for PCR amplification
Plush(F): 5’- CATCCAATTACGTTAACTTGCTGAGGC -3’
Plush(R): 5’- CAGCCAAGGGCATGTTTAACATGAAG -3’
 
PCR program
1) 94°C             2:00
2) 94°C             0:30
3) 56°C             0:30
4) 72°C             1:00
5) repeat steps (2-4) 29X
6) 72°C             7:00
7) 4°C               ∞
 
Primers for sequencing
Plush_seq(F): 5’- TTCGGAGCTGGAAATGCATG -3'
Plush_seq(R): 5’- CTACTGTAGTCATGATCGAGACC -3’
 
The following sequence of 1044 nucleotides (from Genbank genomic region NC_000077 for linear DNA sequence of Krt25 plus 127 additional nucleotides taken from NCBI m37 mouse assembly Chromosome 11: 99177158:99184400) is amplified:
 
-128                                                           catccaa
-121 ttacgttaac ttgctgaggc tggca
agcca ggctttaccc tatgtaggca gaatttcata
 -61 gaacaccctt gagaatcgtc tataaaaggg caaacaaaac catcggggtt agaaggcact
   1 ctagtctgac tctcaagaac acagttcagc gacacgcttg ccctgagatc atgtctcttc
  61 gcctttccag tggatccagg aggtcctatg ctcgccccag cacagggtcg ctcaggggag
 121 ccagcttcgg agctggaaat gcatgtggcg tggcaggcat tggaagtggc ttctcctgcg
 181 ccttcggggg cagctccaca ggaggaaaca cgggggtggc caactcctgt gctggcttca
 241 ctgtgaatga gggggggctc ctctccggca atgagaaggt gaccatgcag aaccttaatg
 301 accgcctggc ctcctacctg gacaacgtgc aagcgctgca ggaggccaac gctgacctgg
 361 agcagaagat caagggctgg tatgaaaaat ttggacctgg gtcgtgccgc ggtctcgatc
 421 atgactacag tagatacttc cccatcattg atgatctaaa aaaccaggta agaaagtata
 481 tttttgcacg tcacatgtat gtagtttact atctaaatgt cctttttact gaaaaaaaaa
 541 aaaagcatgc tacatgatta ctagtggtat ttttaagggc atttaagggc attggaaata
 601 atcatgaagt agattcaagt atttaacttc atgttaaaca tgcccttggc tg  

                                                        
 PCR primer binding sites are underlined; sequencing primer binding sites are highlighted in gray; the mutated T is shown in red text.
References
Science Writers Nora G. Smart
Illustrators Diantha La Vine
AuthorsAmanda L. Blasius, Bruce Beutler
Edit History
2011-01-07 9:41 AM (current)
2010-08-26 4:13 PM
2010-08-26 4:10 PM
2010-02-03 10:35 AM