SOX9 has both conserved and novel roles in marsupial sexual differentiation.
In addition to an essential role in chondrogenesis, SOX9 is a highly conserved and integral part of the testis determining pathway in human and mouse. To determine whether SOX9 is involved in sex determination in noneutherian mammals we cloned a marsupial orthologue and studied its expression. The tammar wallaby SOX9 gene proved to be highly conserved, and maps to a region of the tammar genome syntenic to human chromosome 17. Marsupial SOX9 transcripts were detected by RT-PCR in the developing limb buds and both the developing ovary and testis from the first sign of gonadal development through to adulthood. Northern blot, in situ hybridisation, and immunohistochemical analyses showed that SOX9 reaches high levels of expression in the developing testis, where it is confined to the Sertoli cell nuclei, and the brain. This is similar to the expression pattern seen in human and mouse embryos and is consistent with a conserved role for SOX9 in vertebrate brain, skeletal, and gonadal development. In addition, SOX9 was expressed in the developing scrotum and mammary gland primordium regions of the tammar up to the time of birth. SOX9 protein was also detected in the developing Wolffian duct epithelium in the male mesonephros. These previously undescribed locations of SOX9 expression suggest that SOX9 may play additional roles in the differentiation of the marsupial reproductive system.
Department of Zoology, The University of Melbourne, Melbourne, Australia. a.pask@zoology.unimelb.edu.au
Andrew J
AJ
Pask
Jenny L
JL
Harry
Jennifer A Marshall
JA
Graves
Rachel J Waugh
RJ
O'Neill
Sharon L
SL
Layfield
Geoffrey
G
Shaw
Marilyn B
MB
Renfree
D000595:Amino Acid Sequence; D000818:Animals; D033481:Chromosomes, Mammalian / Q000235:genetics; D003001:Cloning, Molecular; D005260:Female; D020869:Gene Expression Profiling; D006609:High Mobility Group Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007614:Macropodidae / Q000196:embryology* / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D020161:Physical Chromosome Mapping; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055758:SOX9 Transcription Factor; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D006609:High Mobility Group Proteins; D012333:RNA, Messenger; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; C527933:Sox9 protein, mouse; D014157:Transcription Factors