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Specific patterns of histone marks accompany X chromosome inactivation in a marsupial
- Source :
- Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology. 17(1)
- Publication Year :
- 2008
-
Abstract
- The inactivation of one of the two X chromosomes in female placental mammals represents a remarkable example of epigenetic silencing. X inactivation occurs also in marsupial mammals, but is phenotypically different, being incomplete, tissue-specific and paternal. Paternal X inactivation occurs also in the extraembryonic cells of rodents, suggesting that imprinted X inactivation represents a simpler ancestral mechanism. This evolved into a complex and random process in placental mammals under the control of the XIST gene, involving notably variant and modified histones. Molecular mechanisms of X inactivation in marsupials are poorly known, but occur in the absence of an XIST homologue. We analysed the specific pattern of histone modifications using immunofluorescence on metaphasic chromosomes of a model kangaroo, the tammar wallaby. We found that all active marks are excluded from the inactive X in marsupials, as in placental mammals, so this represents a common feature of X inactivation throughout mammals. However, we were unable to demonstrate the accumulation of inactive histone marks, suggesting some fundamental differences in the molecular mechanism of X inactivation between marsupial and placental mammals. A better understanding of the epigenetic mechanisms underlying X inactivation in marsupials will provide important insights into the evolution of this complex process.
Details
- ISSN :
- 15736849
- Volume :
- 17
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology
- Accession number :
- edsair.doi.dedup.....ce9257ab43e67e937b3ea4b997d527bd