Molecular cloning and sequence analysis of a haploid expressed gene encoding t complex polypeptide 1

The mouse t haplotypes show defects in spermatogenesis attributed to multiple loci on chromosome 17. We have cloned the gene for an abundant testicular germ cell protein, t complex polypeptide 1, which has a variant form in t haplotypes, TCP-1A. A cDNA clone, pB1.4, which hybridizes to a 19S mRNA that is abundant in haploid cells during mouse spermatogenesis, derives from the 3' end of the mRNA encoding TCP-1B. The Tcp-1 gene appears to be a member of a novel gene family and shows multiple changes between the predicted amino acid sequences of TCP-1B and TCP-1A. An additional Taq1 site is created by a T to C transition in the predicted open reading frame of the Tcp-1a gene. The resultant RFLP has allowed typing of the Tcp-1 gene cluster in 54 complete and partial t haplotype chromosomes. DNA sequence comparison of the Tcp-1 genes suggests that the t haplotype chromosome arose within the genus Mus more than one million years ago.     

Human homeo box-containing genes located at chromosome regions 2q31----2q37 and 12q12----12q13

Four human homeo box-containing cDNAs isolated from mRNA of an SV40-transformed human fibroblast cell line have been regionally localized on the human gene map. One cDNA clone, c10, was found to be nearly identical to the previously mapped Hox-2.1 gene at 17q21. A second cDNA clone, c1, which is 87% homologous to Hox-2.2 at the nucleotide level but is distinct from Hox-2.1 and Hox-2.2, also maps to this region of human chromosome 17 and is probably another member of the Hox-2 cluster of homeo box-containing genes. The third cDNA clone, c8, in which the homeo box is approximately 84% homologous to the mouse Hox-1.1 homeo box region on mouse chromosome 6, maps to chromosome region 12q12----12q13, a region that is involved in chromosome abnormalities in human seminomas and teratomas. The fourth cDNA clone, c13, whose homeo box is approximately 73% homologous to the Hox-2.2 homeo box sequence, is located at chromosome region 2q31----q37. The human homeo box-containing cluster of genes at chromosome region 17q21 is the human cognate of the mouse homeo box-containing gene cluster on mouse chromosome 11. Other mouse homeo box-containing genes of the Antennapedia class (class I) map to mouse chromosomes 6 (Hox-1, proximal to the IgK locus) and 15 (Hox-3). A mouse gene, En-1, with an engrailed-like homeo box (class II) and flanking region maps to mouse chromosome 1 (near the dominant hemimelia gene). Neither of the class I homeo box-containing genes--c8 and c13--maps to a region of obvious homology to chromosomal positions of the presently known mouse homeo box-containing genes.