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Watch gene expression start to happen in an embryo

Watching dynamics of RNA expression - paper describing a visualization technique.

Movie 1:

Movie 1 from supplemental information: in this zebrafish embryo, DNA is stained with red fluorescence. Carboxyfluoresceinaed Morpholino oligos targeting dre-miR-430 emit visible green fluorescence when they reach sufficient localized concentration. In red you can watch condensation of chromosomes, mitosis, and loosening of the chromatin. After a few divisions you will see green dots appear where groups of miR430 genes are being transcribed and capturing fluorescent-labeled Morpholinos. Each nucleus contains two dots, the maternal and paternal chromosomes revealing the site of miR430 transcription. The green dots disappear as the red chromosomes condense out of the chromatin for mitosis and gene expression halts for division. This movie shows the early-to-mid blastula stages and the onset of zygotic transcription occurs at mid-blastula, so you don't see the green dots appear during the first few cell divisions; early on the cells are expressing maternal mRNAs that are already present in the egg. The onset of zygotic transcription is where the embryo begins to rely on its own genome.

The paper:

Hadzhiev Y, Qureshi H, Wheatley L, Cooper L, Jasiulewicz A, Nguyen HV, Wragg J, Poovathumkadavil D, Conic S, Bajan S, Sik A, Hutvagner G, Tora L, Gambus A, Fossey JS, Mueller F. A cell cycle-coordinated nuclear compartment for Polymerase II transcription encompasses the earliest gene expression before global genome activation. BioRXive. 2018;[Epub]

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