Lecture 3 - The right stuff
The egg from which we come is very dull compared with some of the several hundred cells it gives rise to - nerve cells, muscle cells, bone cells. The differences between all these cells lie in the unique luxury proteins they have (in contrast to the household genes which are common to many cells). For example, haemoglobin is only found in red blood cells, and insulin in special cells in the pancreas. Which of these proteins is made depends on gene action, for proteins are coded for by genes. The genes which are in the cell nucleus can be thought of as a library for the making of proteins and which proteins are 'taken out' is, in a large part, determined by the cytoplasm. The dormant nucleus of the chick red blood cell can be reactivated if placed in the cytoplasm of human cancer cells. Frogs can develop if nuclei from the gut or skin are introduced into an egg whose own nucleus has been removed. Could Frankenstein use this technique to make identical clones of frogs or angels? Which cell type would make a halo?
There are special genes controlling the synthesis of specific proteins in specific cells. By injecting a specially constructed gene (DNA) into the nucleus of a mouse egg it is possible to get growth hormone made in the pancreas whereas normally it is only made in the pituitary gland. Muscle proteins only appear at a particular stage of development. Some of the cells make muscle because of the cytoplasm they acquire when the egg divides whereas others require cell-to-cell interactions.
About the 1986 CHRISTMAS LECTURES
In the 1986 CHRISTMAS LECTURES, Professor Lewis Wolpert (1929-2021) explores developmental biology in a series titled 'Frankenstein's Quest'. Quoting the fictional Dr Frankenstein: "After days and nights of incredible labour and fatigue, I succeeded in discovering the cause of generation and life..." These lectures will look at how life really is generated.
All life comes from cells and all the animals we see about us come from just one cell, the fertilized egg. How does the egg give rise to bats and boys, gnats and girls, eyes and arms? The egg divides and gives rise to many cells which move, multiply, change, and communicate, and from these activities animals emerge through embryonic development. Like an imaginary Frankenstein, we will explore what we need to know in order to control development in order to create not a monster, but an angel.