Positional cloning of Kreisler, a mutation that causes deafness and segmentation abnormalities in mice
- Stanford Univ. School of Medicine, CA (United States)
The identification and analysis of mouse deafness mutations is of great interest to human geneticists, not only because deafness is a common problem in clinical genetics, but also because the molecular mechanisms leading to deafness can underly fundamental aspects of mammalian development. Approximately 10 to 20 genes when mutated can lead to deafness in mice or in humans, but none have yet been identified at the molecular level. In mice homozygous for the kreisler (kr) mutation, abnormal development of the hindbrain and otic vesicle leads to neurosensory deafness and loss of vestibular function. Using the techniques of positional cloning combined with ENU mutagenesis, we have now cloned the kr gene and find that it predicts a transcription factor whose absence leads to defects in Hox gene expression and hindbrain segmentation. We used a backcross between different strains of laboratory mice to sublocalize kr on the meiotic map close to the Src gene on mouse chromosome 2. A probe from the Src gene detected high molecular weight restriction fragments of altered size in kr/kr DNA, suggesting that kr was due to a chromosomal rearrangement. Based on the meiotic map location of kr{sup ENU}, a new kr allele that we generated by ENU mutagenesis, cDNAs were selected from 8.5 day mouse embryos using genomic clones that spanned the distal inversion breakpoint. One cDNA that predicted a basic domain leucine zipper (bZIP) transcription factor was found to be expressed in the caudal hindbrain, and was confirmed to encode the kr gene by analysis of the kr{sup ENU} allele, in which a Ser was substituted for an Asn residue conserved in the DNA binding domain of all known bZip family members. kr is not expressed in the otic vesicle, suggesting that abnormal otic development is a consequence of defects in hindbrain segmentation. kr is the first mammalian deafness gene to be isolated, and should provide insights into embryologic mechanisms that underly hindbrain and otic development.
- OSTI ID:
- 133446
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0174
- 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
Similar Records
Efficient gene-driven germ-line point mutagenesis of C57BL/6J mice
Molecular genetic characterization of the deaf Snell`s waltzer mouse