Germline stem cell maintenance and development


The Hobbs group uses germline stem/progenitor cells from the mouse testis as a model system to define critical mechanisms underlying adult stem cell function. Maintenance of a wide array of adult tissues is dependent on a resident population of rare stem cells that must self-renew plus generate differentiating daughter cells. The appropriate control of stem cell self-renewal and differentiation is critical for tissue homeostasis while disruption of the balance between these processes can contribute to tissue degeneration or cancer. In adult testis, there is a population of germline stem/progenitor cells (known as spermatogonial stem and progenitor cells or SSPCs) that are required for life-long production of differentiating germ cells and spermatozoa.

A handful of cell intrinsic factors are known to be involved in SSPC maintenance, foremost amongst which is the transcription factor Promyelocytic Leukemia Zinc Finger (Plzf). A major focus of the group is to define downstream targets of Plzf in SSPCs and their role in SSPC function. This is achieved by using a combination of mouse genetics, flow cytometry analysis and in vitro culture techniques.

The principal aim of this research is to identify and characterize novel molecular mechanisms underlying adult stem cell function.

Robin Hobbs established his research group at Monash University in 2012 with the support of a Larkin’s Fellowship and is currently an ARC Future Fellow. He has a joint appointment with the Australian Regenerative Medicine Institute (ARMI) and the Department of Anatomy and Developmental Biology. The primary focus of his laboratory is to define critical mechanisms underlying adult stem cell fate decisions, whether to self-renew or differentiate, using germline stem cells from the testis as a model.

Prior to establishing his group at Monash, Robin performed PhD studies with Prof. Fiona Watt at Cancer Research UK, London and postdoctoral work with Prof. Pier Paolo Pandolfi associated with Harvard Medical School, Boston.

During his postdoctoral studies, he characterized a key and unexpected role for the transcription factor and tumour suppressor gene Plzf in self-renewal of male germline stem cells (spermatogonial stem/progenitor cells; SSPCs). PLZF has since become a well-established marker for SSPCs and his subsequent work has focused on identifying novel regulators of SSPC function and fertility.

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Hobbs, R.M. et al.

Functional Antagonism between Sall4 and Plzf Defines Germline Progenitors.

Cell Stem Cell. 2012 Mar 2;10(3):284-98. doi: 10.1016/j.stem.2012.02.004.

Hobbs, R.M., Seandel, M., Falciatori, I., Rafii, S. & Pandolfi, P.P.

Plzf regulates germline progenitor self-renewal by opposing mTORC1.

Cell. 2010 Aug 6;142(3):468-79. doi: 10.1016/j.cell.2010.06.041.

Seandel, M. et al.

Generation of functional multipotent adult stem cells from GPR125+ germline progenitors.

Nature. 2007 Sep 20;449(7160):346-50.

Costoya, J.A. and Hobbs, R.M. et al.

Essential role of Plzf in maintenance of spermatogonial stem cells.

Nat Genet. 2004 Jun;36(6):653-9. Epub 2004 May 23.