Cloning of the mouse steroid sulfatase (Sts) gene
- UCSF School Medicine, San Francisco, CA (United States)
- UCSF Sch. Medicine, San Francisco, CA (United States); and others
In humans, the STS gene is located on the distal short arm of the X chromosome, proximal to the pseudoautosomal region (PAR). STS activity can be detected in mouse tissues using the same substrates as for the human STS assay, and quantitative differences in STS levels among various mouse strains allowed the mapping of Sts to the PAR. However, several attempts to clone the mouse Sts gene using human reagents have failed, which has been taken as evidence of substantial divergence between these genes. We report the cloning of the mouse Sts gene by using the Sts cDNA from an intermediate species, the rat. The coding region of the rat Sts cDNA was used as a probe to screen mouse fibroblast and liver cDNA libraries, and 5 clones were isolated. DNA sequence of the 2.5 kb cDNA revealed 75% similarity with rat Sts, while it was only 63% and 60% similar to the human STS at the DNA and protein levels, respectively. Interestingly, the mouse Sts cDNA revealed a high GC content, including 225 CpG dinucleotides in the coding region, compared to 88 and 44 CpGs in the same regions of the rat and human STS genes, respectively. Despite the low degree of conservation between these genes, all the point mutations described so far in human STS-deficient patients occur at amino acid residues that are conserved between these three species. Using a panel of mouse-hamster somatic cell hybrids, the mouse Sts cDNA sequences were mapped to the mouse X and Y chromosomes, with restriction fragments of the same size for both chromosomes, consistent with localization of Sts in the PAR. The pseudoautosomal pattern of inheritance was ascertained in back-crosses between C3H/An and SW mice, making use of STS activity assays and RFLPs. RT-PCR experiments using cDNA from a panel of hamster-mouse somatic cell hybrids containing either the inactive or the active X chromosome indicated that the mouse Sts gene escapes X-inactivation, as expected for a pseudoautosomal gene.
- OSTI ID:
- 133869
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0603
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BASIC STUDIES
GENES
DNA-CLONING
GENETIC MAPPING
GENE MUTATIONS
GENETICS
STRUCTURE-ACTIVITY RELATIONSHIPS
RATS
COMPARATIVE EVALUATIONS
STEROIDS
HUMAN POPULATIONS
MICE
SOMATIC CELLS
HYBRIDIZATION
DNA SEQUENCING
NUCLEOTIDES
PROTEINS
HETEROCHROMOSOMES
PROBES
AMINO ACIDS
RFLPS
POLYMERASE CHAIN REACTION