Expression of the IV (reversed and/or heterotaxic) phenotype in SWV mice
| Autor: | M. W. Layton, Fred G. Biddle, Margaret L. Van Keuren, Andrzej J. Hanzlik, W. M. Layton, Michael Binder, David M. Kurnit |
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| Rok vydání: | 1993 |
| Předmět: |
Male
congenital hereditary and neonatal diseases and abnormalities Embryology Heterozygote Health Toxicology and Mutagenesis Gene Expression Biology Toxicology Mice Gene interaction Inbred strain Species Specificity Gene expression otorhinolaryngologic diseases medicine Animals Allele Chromosome 12 Crosses Genetic Genetics Heterozygote advantage medicine.disease Situs Inversus Molecular biology Situs inversus medicine.anatomical_structure Phenotype Female Situs solitus Developmental Biology |
| Zdroj: | Teratology. 47(6) |
| ISSN: | 0040-3709 |
| Popis: | Approximately 50% of iuliu mice have situs incersus (mirror image reversal of viscera) and 40% have heterotaxia (anomalous arrangement of viscera). The occurrence of heterotaxia is independent of situs. Using the cross-intercross breeding system to put the iv gene on the SWV background, an occasional presumed iuli mouse was found that had an IV (situs inucrsus and/or heterotaxic) phenotype. Testcrosses of these reversed animals indicated an iui t genotype. Since iv is linked tightly to Igh-C on chromosome 12, we inferred the genotype with a polymorphism of Igh-C demonstrated using the polymerase chain reaction (PCR). This confirmed them to be ivi + . The expression of the IV phenotype in animals heterozygous for the tu gene may be due to an interaction of iv with an autosomal recessive gene found in SWV. We have not found the IV phenotype in heterozygous iui + mice following placement of the it, gene on six other inbred strains. Rarely, we also found that presumed SWV + + mice had the IV phenotype. Test matings of these phenodcviants, corroborated by PCR, have confirmed them to be +I + . Although the phenotypes of the affected SWV +I + and ivl + mice resembled those found in iviiu mice, the occurrence of situs inversus and heterotaxia were not independent of each other, and most, of the SWV mice with the IV phenotype had heterotaxia with situs solitus. This infrequent. dominant expression of the iv gene has so far only been seen when iv is on the SWV background. These findings are consistent with the idea that this phenomenon is due to the interaction of the iv gene with another gene found so far only in the SWV strain. (~8 1993 Wiley-Liss, Inc. The autosomal recessive gene iu (Hummel and Chapman, '59), which maps to chromo- some 12 (Brueckner et al., '89), causes situs inuersus (mirror image reversal of place- ment of organs) in mice. One half of iuliu mice have situs inuersus and approximately 40% have some sort of heterotaxia, an ab- normal arrangement of organs in relation to each other. Heterotaxia occurs indepen- dently of visceral situs in ivliv mice, so that the frequency of heterotaxia in mice with situs inversus is equal to its frequency in those with situs solitus (normal placement of organs). In mouse strains examined pre- viously, ivl + heterozygotes have demon- strated normal laterality indicating that the iu gene is a loss-of-function allele: in the absence of iu gene activity in the ii)!ii$ mouse, laterality determination does not oc- cur resulting in the random determin a t' ion of visceral .situs (Layton, '76; Kurnit et al., '87). |
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