Defining the spermatogonial stem cell

Franklin K Hamra, Nikolaus Schultz, Karen M. Chapman, Dana M. Grellhesl, Jennifer T. Cronkhite, Robert E Hammer, David L. Garbers

Research output: Contribution to journalArticlepeer-review

123 Scopus citations


Through the use of donor cells from transgenic rats expressing GFP exclusively in the germline, we have defined culture conditions where male germ cells lose (on STO cells) or maintain (on MSC-1 cells) stem cell activity. A cadre of germ cell transcripts strikingly decrease in relative abundance as a function of testis age or culture time on STO cells, but only a subset of these transcripts (approximately 248) remain elevated when cultured on MSC-1 cells. If specific gene expression regulates stem cell activity, some or all of these transcripts are candidates as such regulators. We establish a spermatogonial stem cell index (SSCI) that reliably predicts relative stem cell activity in rat or mouse testis cell cultures, and through the use of an antibody to a robust signal (Egr3) within the index find intense signals in single or paired cells. As germ cells form longer interconnected chains (incomplete cytokinesis), the Egr3 signal disappears coincident with a loss of stem cell activity. Thus, molecular markers specific for spermatogonial stem cells establish a reliable and rapid means by which to define these cells in culture and alleviate the need for laborious testicular transfers in initial cell culture studies.

Original languageEnglish (US)
Pages (from-to)393-410
Number of pages18
JournalDevelopmental Biology
Issue number2
StatePublished - May 15 2004


  • Male germ cells
  • Microarray
  • Mouse
  • Rat
  • Spermatogonia
  • Spermatogonial stem cells
  • Stem cell index
  • Stem cells
  • Testis colonization
  • Transcript profile

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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