Strain Name:


Stock Number:



Awaiting Transfer from the Donor

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These mice carry a germline knockout of the Lin28a (lin-28 homolog A (C. elegans)) gene. Homozygous mice show dwarfism and most die within 1 day of birth (many showing cardiac ventricular septal defects). Survivors exhibit decreased bone mineral density.


Strain Information

Type Congenic; Mutant Strain; Targeted Mutation;
Additional information on Genetically Engineered and Mutant Mice.
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Additional information on Congenic nomenclature.
Specieslaboratory mouse
Donating Investigator George Q. Daley,   Children's Hospital Boston

LIN28A (lin-28 homolog A (C. elegans)) is an RNA-binding protein that blocks biogenesis of Mirlet7 (let-7) microRNAs. Let-7 targets are known regulators of mammalian body size and metabolism.

These mice carry a germline knockout of the Lin28a gene. Homozygous mice show dwarfism as early as E13.5 and by E18.5 demonstrate a 20% reduction in weight relative to heterozygous controls. Although born at expected Mendelian ratios, roughly 93% of Lin28a knockout mice die within 1 day of birth (2 out of 5 mice harboring a cardiac ventricular septal defect). Those animals that survive are 30-50% smaller in weight and 20-30% shorter in length than controls. Dual-energy x-ray absorptiometry imaging confirms a decreased fat mass and also reveals decreased bone mineral density in the knockout animals, suggesting that these animals suffer from metabolic dysregulation.

Exon 2 was flanked by loxP sites and an FRT-flanked neomycin cassette was introduced through homologous recombination in (C57BL/6 x 129S4/SvJae)F1-derived v6.5 embryonic stem (ES) cells. Mice were crossed to inbred C57BL/6 for ten generations then bred with FVB background germline-specific Ddx4-cre mice (see Stock No. 006954) to excise the floxed region. This strain was backcrossed to FVB for 8 generations by the donating lab.

Control Information

   Wild-type from the colony
  Considerations for Choosing Controls

Related Strains

Strains carrying other alleles of Lin28a
023913   B6.Cg-Lin28atm1.2Gqda/J
023915   B6.Cg-Lin28atm2.1Gqda Lin28btm2.1Gqda/J
View Strains carrying other alleles of Lin28a     (2 strains)


Phenotype Information

View Mammalian Phenotype Terms

Mammalian Phenotype Terms provided by MGI
      assigned by genotype

The following phenotype information may relate to a genetic background differing from this JAX® Mice strain.


        involves: 129S4/SvJae * C57BL/6 * FVB
  • reproductive system phenotype
  • decreased germ cell number
  • reduced fertility   (MGI Ref ID J:196313)


        involves: 129S4/SvJae * C57BL/6
  • mortality/aging
  • partial neonatal lethality
    • nearly all mice die within 1 day of birth   (MGI Ref ID J:199720)
  • growth/size/body phenotype
  • decreased body size
    • in surviving mice   (MGI Ref ID J:199720)
    • decreased body length
      • in surviving mice   (MGI Ref ID J:199720)
    • decreased body weight
      • in surviving mice   (MGI Ref ID J:199720)
  • decreased embryo weight
    • dwarfism at E13.5   (MGI Ref ID J:199720)
  • decreased fetal weight
  • decreased total body fat amount
    • severe in surviving mice   (MGI Ref ID J:199720)
  • homeostasis/metabolism phenotype
  • abnormal glucose homeostasis
    • lower flux in glycolysis at E10.5   (MGI Ref ID J:199720)
  • cellular phenotype
  • abnormal cell physiology
    • dysregulation of pyrimidine metabolism at E10.5   (MGI Ref ID J:199720)
  • adipose tissue phenotype
  • decreased total body fat amount
    • severe in surviving mice   (MGI Ref ID J:199720)
  • cardiovascular system phenotype
  • ventricular septal defect   (MGI Ref ID J:199720)
  • skeleton phenotype
  • decreased bone mineral density
    • in surviving mice   (MGI Ref ID J:199720)
  • embryogenesis phenotype
  • decreased embryo weight
    • dwarfism at E13.5   (MGI Ref ID J:199720)
  • muscle phenotype
  • *normal* muscle phenotype
    • mice exhibit normal muscle histology   (MGI Ref ID J:199720)
View Research Applications

Research Applications
This mouse can be used to support research in many areas including:

Developmental Biology Research
Growth Defects
      Growth Defects (homozygous)
Postnatal Lethality
Skeletal Defects

Internal/Organ Research

Metabolism Research
Lipid Metabolism

Genes & Alleles

Gene & Allele Information provided by MGI

Allele Symbol Lin28atm1.1Gqda
Allele Name targeted mutation 1.1, George Q Daley
Allele Type Targeted (knock-out)
Strain of Origin(C57BL/6 x 129S4/SvJae)F1
Gene Symbol and Name Lin28a, lin-28 homolog A (C. elegans)
Chromosome 4
Gene Common Name(s) AL024421; CSDD1; LIN-28; LIN28; Lin28; RGD1566408; Tex17; ZCCHC1; expressed sequence AL024421; lin-28 homolog (C. elegans); lin-28A; testis expressed gene 17;
Molecular Note A loxP site was inserted upstream of exon 2. An FRT flanked neo cassette with a 5' loxP site was inserted downstream of exon 2 via homologous recombination. Cre-mediated recombination removed exon 2. [MGI Ref ID J:196313]


Genotyping Information

Helpful Links

Genotyping resources and troubleshooting


References provided by MGI

Selected Reference(s)

Shinoda G; De Soysa TY; Seligson MT; Yabuuchi A; Fujiwara Y; Huang PY; Hagan JP; Gregory RI; Moss EG; Daley GQ. 2013. Lin28a regulates germ cell pool size and fertility. Stem Cells 31(5):1001-9. [PubMed: 23378032]  [MGI Ref ID J:196313]

Additional References

Lin28atm1.1Gqda related

Shinoda G; Shyh-Chang N; de Soysa TY; Zhu H; Seligson MT; Shah SP; Abo-Sido N; Yabuuchi A; Hagan JP; Gregory RI; Asara JM; Cantley LC; Moss EG; Daley GQ. 2013. Fetal Deficiency of Lin28 Programs Life-Long Aberrations in Growth and Glucose Metabolism. Stem Cells :. [PubMed: 23666760]  [MGI Ref ID J:199720]

Health & husbandry

Health & Colony Maintenance Information

Colony Maintenance

Breeding & HusbandryHeterozygotes are viable and fertile. Most homozygotes die within 1 day of birth, many having a cardiac ventricular septal defect.

Pricing and Purchasing

Pricing, Supply Level & Notes, Controls


This strain is currently Awaiting Transfer from the Donor.

Register Interest

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Control Information

   Wild-type from the colony
  Considerations for Choosing Controls
  Control Pricing Information for Genetically Engineered Mutant Strains.

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The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project.
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