A structural gene (Tcp-1) within the mouse t complex is separable from effects on tail length and lethality but may be associated with effects on spermatogenesis

Abstract

SUMMARY: The Tcp-1 gene is located within the t complex and codes for a major testicular cell protein called p63/6.9. All wild-type chromosomes carry the Tcp-1^b allele which codes for a basic form of this protein, while all complete t haplotypes carry the Tcp-1^a allele which codes for an acidic form of this protein. It is not clear whether the Tcp-1 gene is associated with phenotypic effects of t haplotypes on embryogenesis and/or spermatogenesis, since the genetic basis for these effects is extremely complex. The elegant analysis of Lyon & Mason (1977) has allowed the identification and separation of a family of genetic factors which interact to produce the observed phenotypes associated with various combinations of t haplotypes. The data summarized in this report indicate that the Tcp-1^a locus is separable from all of the identified t haplotype factors except for one; a complete correlation has been obtained between Tcp-1^a and a proximal t haplotype factor which is involved in effects on transmission ratio distortion. Two other novel points emerge from this analysis. First, it appears that the tail interaction factor and the proximal sperm factors represent distinct genetic loci. Second, the accumulated data lead to the proposal that the T^Orl chromosome carries a short segment of t haplotype chromatin containing Tcp-1^a and proximal sperm factors involved in transmission ratio distortion and sterility.