Cfc1 (cripto, FRL-1, cryptic family 1) encodes an extracellular protein containing a divergent epidermal growth factor (EGF) motif and a conserved cysteine-rich (CFC) domain; it is essential for left-right axis formation in the developing embryo. Cfc1 is expressed in the lateral plate mesoderm, node, notochordal plate, and prospective floor plate from head-fold stages through the eight somite stage. Like other EGF-CFC proteins, CFC1 can mediate signaling through Nodal, a factor that is required for axial formation. Cryptic knockout mice contain a neomycin cassette designed to replace exons 4-5 and part of exon 3, abolishing gene function. Heterozygous mice are viable, fertile, and normal in size. Homozygotes die within the first two weeks after birth due to cardiac defects. Homozygotes display asplenia or severe hyposplenia, abnormal lobation or midline positioning of the liver, right pulmonary isomerism, transposition of the great arteries, cardiac looping, and randomized embryo turning. Half of homozygous mice display inverted situs of the stomach, spleen, and pancreas, as well as dextrocardia or mesocardia. Cryptic mice also exhibit defects within the vasculature consistent with heterotaxia. This strain may be useful for studying left-right axis specification during embryo development.

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Cryptic knock-out mice have exons 4-5 and part of exon 3 deleted in the Cfc1 (cripto, FRL-1, cryptic family 1) gene. Homozygotes exhibit left-right laterality defects and most homozygous mice die in the first two weeks of birth due to cardiac defects. This strain may be useful for studying left-right axis specification during embryo development.

This strain is hosted by NIH's MMRRC, which partners with JAX for the distribution of this and other strains. For additional information and to purchase, please visit the MMRRC site.