Changes in DNA loop domain structure during spermatogenesis and embryogenesis in the syrian golden hamster

A. V. Klaus, J. R. McCarrey, A. Farkas, W. S. Ward

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The DNA in eukaryotic cells is organized into loop domains that are 25 to 100 kilobases long and attached at their bases to the nuclear matrix. This organization plays major roles in DNA replication and transcription. We examined changes in DNA loop structure of the 5S rDNA gene cluster in the Syrian golden hamster as a function of cellular differentiation by direct visualization with fluorescent in situ hybridization. The 5S rDNA cluster is large enough to encompass more than one loop domain but small enough that individual loop domains can still be resolved. We found that the sizes of the 5S rDNA loops are much smaller, and that the numbers of loops per locus are larger, in all pluripotent cell types than they are in adult somatic tissue. Within the pluripotent spermatogenic cell lineage, the loop domain organization was cell specific. The loop size decreased during the early stages of spermatogenesis but did not change during spermiogenesis, suggesting that DNA loop structure is independent of the chromatin condensation that occurs when protamines replace histones. In early embryonic cells, the loop structure remained small, but in differentiated somatic cells, it became much larger. We suggest that these changes in the 5S rDNA loop domain structure may be related to the maintenance or loss of developmental potential.

Original languageEnglish (US)
Pages (from-to)1297-1306
Number of pages10
JournalBiology of reproduction
Issue number5
StatePublished - 2001
Externally publishedYes


  • Developmental biology
  • Implantation/early development
  • Sperm
  • Spermatid

ASJC Scopus subject areas

  • Reproductive Medicine


Dive into the research topics of 'Changes in DNA loop domain structure during spermatogenesis and embryogenesis in the syrian golden hamster'. Together they form a unique fingerprint.

Cite this