Roads to polyploidy: the megakaryocyte example.
Polyploidy, recognized by multiple copies of the haploid chromosome number, has been described in plants, insects, and in mammalian cells such as, the platelet precursors, the megakaryocytes. Several of these cell types reach high ploidy via a different cell cycle. Megakaryocytes undergo an endomitotic cell cycle, which consists of an S phase interrupted by a gap, during which the cells enter mitosis but skip anaphase B and cytokinesis. Here, we review the mechanisms that lead to this cell cycle and to polyploidy in megakaryocytes, while also comparing them to those described for other systems in which high ploidy is achieved. Overall, polyploidy is associated with an orchestrated change in expression of several genes, of which, some may be a result of high ploidy and hence a determinant of a new cell physiology, while others are inducers of polyploidization. Future studies will aim to further explore these two groups of genes.
Ravid
Katya
K
Department of Biochemistry, Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA. ravid@med-biochem.bu.edu
Lu
Jun
J
Zimmet
Jeffrey M
JM
Jones
Matthew R
MR
D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism; D011123:Polyploidy
D018797:Cell Cycle Proteins