The "Goldilocks effect" in fruit fly embryos may be more intricate than previously thought. It's been known that specific proteins, called histones, must exist within a certain rangeif there are too few, a fruit fly's DNA is damaged; if there are too many, the cell dies. Now research out of the University of Rochester shows that different types of histone proteins also need to exist in specific proportions. The work further shows that cellular storage facilities keep over-produced histones in reserve until they are needed.
Associate Professor of Biology Michael Welte has discovered that the histone balance is regulated by those storage facilities, called lipid dropletswhich are best known as fat depots.
The findings were published today in the journal Current Biology.
Welte had previously discovered that another proteincalled Jabbaanchored histones onto lipid droplets. In his latest research, he found that excess histones migrate outside the nucleus to the droplets, where they are temporarily held until needed to create new chromosomes.
"People have observed histone proteins on lipid droplets in multiple organisms, including mammals," said Welte. "The results of this research project may very well help us understand the role of histones and lipid droplets in humans."
Welte found that by deleting the Jabba anchors from the cell, one particular type of histone increased in proportion in the nucleus, since they had no way to be held in reserve away from the cell nuclei. That made the embryo more sensitive to environmental stresses like higher temperature, leading to defects during cell division and reduced viability.
Just as it is in humans, the embryonic stage is a crucial time for the fruit fly (Drosophila melanogaster). Starting from a single cell, it has to rapidly multiply in cell number and develop into a larva while coping with stresses from the environment. The embryo does all of t
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University of Rochester