A team of scientists worked on quail eggs to get a close, real-time video of developing fetuses in order to understand more clearly the possible cause behind birth defects and other health issues.
Developing Embryo in Closer View
Avian embryos are considered an excellent model of human development, especially in the early phases of growth. This is due to the similarity in the development of many major organs, such as the heart and neural tube.
Quail embryos are also easier to record alive as they grow because the thin shell of an egg makes it easier for medical technology to peer through and leave it undisturbed. In human embryos, it is very difficult to take pictures of these stages of embryonic development as they occur after they have been implanted into the mother's womb.
In a recent study, scientists have just captured the very first view of an early-stage embryo formation. In the paper "A Lifeact-EGFP quail for studying actin dynamics in vivo," the research authors report the generation of a transgenic Lifeact-EGFP quail line.
Led by Yanina D. Alvarez, the molecular bio-scientists from the University of Queensland in Australia used fluorescent protein to illuminate the cells within the tiny embryo. The genes for creating these proteins were implanted into the live quail embryo through direct injection into its blood-circulating primordial germ cells.
Such fluorescent proteins light up the actin cytoskeleton or early protein scaffolding of an embryo. This cytoskeleton provides a shape to hold onto the cells and also helps them move.
The fluorescent protein is also bound selectively to actin, lighting it up and defining the early embryonic structure. With this illumination, scientists were able to record how individual cells formed armlike protrusions that help the cells crawl along the cytoskeleton's protein supports into the right place.
Scientists were more than surprised as they watched the cells of a quail embryo crawl around its protein-based support structure and organize themselves into the earliest form of a heart and the very first phase of its spine and brain.
Solving Birth Defects During Embryonic Development
One of the significant events recorded by the Australian team of scientists was the 'zipping up' of cells along the long open edges of the embryo's neural tube. Cells fold into this tube-like shape and then seal into a tube in a kind of zipper motion as cells' small arm-like projections called the lamellipodia and filopodia link up.
This neural tube, once closed off, will continue growing and mature into its future shape as the brain and spinal cord.
It is exactly this process which often gets disrupted during the fourth week of human development. Whether inherited or induced by environmental factors, this disruption leads to congenital birth defects of the brain or spine.
Studies have shown that around 3-4% of all babies born are affected with some kind of congenital birth defect, mainly those related to heart and neural tube defects. Current treatments available are surgeries just after birth, while in worse cases, transplants for heart defects may also be necessary.
Since quail eggs are similar in type to the human kind in the early stages of embryo formation, the researchers want to study the very early steps involved in embryonic cells leading to birth defects.
The research team plans to find proteins or genes that can be triggered in the future or used for screening for congenital birth defects. They are currently studying how mutations identified in patients of maternal factors disrupt this development and lead to congenital defects.
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