Identification of novel genes required for gonadal development

Summary

Our aim is to identify the underlying molecular and cellular events that cause human disorders of sexual development. As one approach, we are undertaking an ENU mutagenesis screen to identify novel genes involved in gonad development. We have identified several mutant strains affecting testis development which are currently under investigation.

Description

Our aim is to identify novel genes that underlie human disorders of sexual development. In collaboration with the Department of Anatomy at Monash University, we are undertaking an ENU mutagenesis screen in mice at the Australian Phenomics Facility (APF), which is a National Facility based at the Australian National University (ANU) in Canberra.

As a mutagen, ENU offers several advantages:

(i) it is efficient and potent, inducing ~1 mutation per 0.5-1 megabase (Mb) of the genome (30 exonic mutations per pedigree);

(ii) the mutations are essentially random, hence any gene can be mutated;

(iii) it creates single base pair (point) changes, hence replicates the most common type of spontaneous mutation in the human genome;

(iv) different pedigrees of mice can carry different point mutations within the same gene, thereby creating an allelic series, each able to reveal a different function in the protein the gene encodes.

We are currently screening 50 pedigrees per year. Mouse embryos at embryonic days 13.5 and 18.5 are screened for abnormalities in testicular and ovarian development. We have identified several mutant strains affecting testis development which are currently under investigation. The causual mutations will be identified by backcrossing to the inbred mapping strain C3H.

We are also undertaking a sensitized ENU mutagenesis screen to identify genes involved in sex determination. We found that heterozygous Sox9 knockout mice are sensitized for XY sex reversal. While mice lacking one copy of the Sox9 gene do not show a gonadal phenotype, mice lacking one gene copy of each Sox9 and Fgfr2 display partial sex reversal (ovotestes).

Funding

National Health and Medical Research Council
National Collaborative Research Infrastructure Strategy (NCRIS)
Monash Strategic Grants Scheme

Outcomes

Identified novel genes involved in human disorders of sexual development

Selected Publications

Beverdam, A., Svingen, T., Bagheri-Fam, S., Bernard, P., McClive, P., Robson, M., Khojasteh, M.B., Salehi, M., Sinclair, A.H., Harley, V.R., and Koopman, P. (2009). Sox9-dependent expression of Gstm6 in Sertoli cells during testis development in mice. Reproduction 137:481-486.

Bagheri-Fam, S., Sim, H., Bernard, P., Jayakody, I., Taketo, M.M., Scherer, G. and Harley, V.R.(2008). Loss of Fgfr2 leads to XY gonadal sex reversal. Developmental Biology 314, 71-83.

Barrionuevo, F., Bagheri-Fam, S., Klattig, J., Kist, R., Taketo, M.M., Englert, C. and Scherer, G. (2006). Homozygous inactivation of Sox9 causes complete XY sex reversal in mice. Biology of Reproduction 74, 195-

PHI Research Team