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<\/a><\/p>\nThe Polo protein is required for proper regulation of several essential processes during mitotic cell division.\u00a0 In the absence of Myb, the expression of Polo is greatly reduced.\u00a0 However, in the absence of both Myb and Mip130 normal levels of\u00a0 Polo expression occur in ~50% of cells in the imaginal wing disc (a larval tissue that will become the adult wing).\u00a0 Cells that express either high or low levels of Polo in a Myb, Mip130 double mutant background are not randomly distributed throughout the tissue.\u00a0 Instead, it appears that the decision to turn Polo “OFF” or “ON” is made early in development and then maintained during subsequent mitotic cell divisions.\u00a0 Such a mottled pattern of gene expression is often referred to as “variegation”.\u00a0 These results imply that the Myb-MuvB\/DREAM complex is required for the proper initiation but not for the subsequent maintenance of this epigenetic state.<\/p>\n
The function of the Myb-MuvB\/DREAM complex is not limited to regulation of the cell division cycle.\u00a0 The ability to accurately detect odors depends on the expression of one and only one odorant receptor in each olfactory neuron.\u00a0 The correct odorant receptor genes must be turned “ON” and all other odorant receptor genes must be turned “OFF”.\u00a0 Analysis of mutant Drosophila in collaboration with the laboratory of Anand Ray (UC Riverside) showed that Myb is required to keep the carbon dioxide receptor “ON” in the correct neurons and other members of the Myb-MuvB\/DREAM complex are required to keep the carbon dioxide receptor “OFF” in the wrong neurons.\u00a0 The carbon dioxide receptor is of particular interest because mosquitoes use the homologous receptor to identify humans as a food source.<\/p>\n The images above are of adult Drosophila brains.\u00a0 Neurons expressing Gr63a (red), a subunit of the carbon dioxide receptor, normally project from the olfactory tissue (not shown) to a small region within the antennal lobe of the brain (left panel).\u00a0 In the absence of Mip120, many neurons that project to other areas of the brain abnormally express Gr63a (right panel).<\/p>\n","protected":false},"excerpt":{"rendered":" In contemporary usage, the word “epigenetic” refers to the inheritance of stable states of gene expression that are not due to differences in the DNA sequence of an organism or its cells.\u00a0 For example, almost all cells in the human body contain the same DNA sequence.\u00a0 However,\u00a0 lung cells divide and give rise to new … Continue reading Epigenetic Regulation by Myb and Friends<\/span> <\/a><\/p>\n<\/a><\/p>\n