Oral Presentation ESA-SRB-ANZOS 2025 in conjunction with ENSA

Gene expression dynamics during early gonadal differentiation in the tammar wallaby (128651)

Trent Newman 1 , Yu Chen 1 , Monika R Paranjpe 2 , Geoff Shaw 2 , Marilyn B Renfree 2
  1. The University of Melbourne, PARKVILLE, VIC, Australia
  2. School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia

*These authors contributed equally

Ovaries and testes develop from a bipotential gonad. Tammar wallabies deliver a highly altricial young, and while the bipotential gonad is formed at day 21 of the 26.5 day gestation, the testes and ovaries remain undifferentiated at birth (1). By 2 days postpartum (dpp), testicular cords enclosing germ cells are distinct in males. In females, ovarian differentiation starts later, with ovigerous cords and germ cell nests starting to form in the ovarian cortex between 2-4 dpp (1, 2). Expression profiles of key eutherian gonadal differentiation regulators, including FOXL2, WNT4, SOX9 and AMH, have been assessed in tammar gonads (3-5) and after exposure to estrogen and bisphenol A (2, 5). However, to identify novel candidate regulators, we focussed on 2 dpp and 8 dpp in both ovaries and testes.

We performed RNA-seq on tammar gonads collected at 2 and 8 dpp, the period of gonadal differentiation, and profiled differential gene expression. From 2-8 dpp, there was a developmental increase in known testicular markers (HSD17β3, CYP17A1, INSL3, ATRX), as well as in novel genes including NWD1, a gene associated with prostate cancer and Interleukin-1 receptor type 2. In ovaries, there was a developmental increase in DDX4 coinciding with the postnatal germ cell proliferation. Developmental changes in the ovary were enriched for gene ontology terms associated with cell cycle regulation, germ cell development, piRNA processing, morphogenesis and neuronal development. Based on significant changes in expression potential regulators of early ovary development include, for example, Serpin B2 and Suppressor of glucose autophagy associated 2.

The function of these genes in gonadal development is as yet unknown, but the long period of differentiation after birth in the tammar allows us a unique opportunity to define their action to further understand the control of mammalian gonadal development.

  1. Renfree, M. B., O, W-S., Short, R. V., & Shaw, G. (1996). Sexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii. Anatomy and Embryology, 194, 111-134.
  2. Peiris, M. T., Chen, Y., Shaw, G., & Renfree, M. B. (2025). Early ovarian differentiation in the tammar wallaby and the effects of exposure to bisphenol A. Reproduction, 169(1).
  3. Paranjpe, M., Chen, Y., Shaw, G., & Renfree, M. B. (2025). Ontogeny of RSPO1, FOXL2, and RUNX1 during ovarian differentiation in the marsupial tammar wallaby. Developmental Dynamics.
  4. Yu, H., Pask, A. J., Shaw, G., & Renfree, M. B. (2006). Differential expression of WNT4 in testicular and ovarian development in a marsupial. BMC Developmental Biology, 6, 1-13.
  5. Paranjpe, M., Yu, H., Frankenberg, S., Pask, A. J., Shaw, G., & Renfree, M. B. (2020). Transcriptomic analysis of MAP3K1 and MAP3K4 in the developing marsupial gonad. Sexual Development, 13(4), 195-204.