Enzyme Gene Quotes & Sayings

In this model, there is a vicious cycle of events that results in the generation of a more and more repressed state. One of the predictions from this model is that repressive histone modifications attract DNA methyltransferases, which deposit DNA methylation near those histones. This methylation in turn attracts more repressive histone modifying enzymes, creating a self-perpetuating cycle that leads to an increasingly hostile region for gene expression. Experimental data suggest that in many cases this model seems to be right. Repressive histone modifications can act as the bait to attract DNA methylation to the promoter of a tumour suppressor gene. A key example of this is an epigenetic enzyme we met in the previous chapter, called EZH2. The EZH2 protein adds methyl groups to the lysine amino acid at position 27 on histone H3. This amino acid is known as H3K27. K is the single letter code for lysine (L is the code for a different amino acid called leucine). — Nessa Carey

As has repeatedly been stated, the underlying hypothesis, which in a number of cases has been supported by direct experimental evidence, is that each gene controls the production, function, and specificity of a particular enzyme. — Edward Lawrie Tatum

A microscopic egg had failed to divide in time due to a failure somewhere along a chain of chemical events, a tiny disturbance in a cascade of protein reactions. A molecular event ballooned like an exploding universe, out onto the wider scale of human misery. No cruelty, nothing avenged, no ghost moving in mysterious ways. Merely a gene transcribed in error, an enzyme recipe skewed, a chemical bond severed. A process of natural wastage as indifferent as it was pointless. Which only brought into relief healthy, — Ian McEwan

There is increasing evidence that at least some of the targeting of epigenetic modifications can be explained by interactions with long ncRNAs. Jeannie Lee and her colleagues have recently investigated long ncRNAs that bind to a complex of proteins. The complex is called PRC2 and it generates repressive modifications on histones. PRC2 contains a number of proteins, and the one that interacts with the long ncRNAs is probably EZH2. The researchers found that the PRC2 complex bound to literally thousands of different long ncRNA molecules in embryonic stem cells from mice13. These long ncRNAs may act as bait. They can stay tethered to the specific region of the genome where they are produced, and then attract repressive enzymes to shut off gene expression. This happens because the repressive enzyme complexes contain proteins like EZH2 that are capable of binding to RNA. — Nessa Carey

A key issue in developmental biology at that time was the problem of how cells underwent differentiation, with most workers concentrating on explanations in terms of changes in enzyme and gene regulation. — Paul Nurse

Soon after Harris's HeLa-chicken study, a pair of researchers at New York University discovered that human-mouse hybrids lost their human chromosomes over time, leaving only the mouse chromosomes. This allowed scientists to begin mapping human genes to specific chromosomes by tracking the order in which genetic traits vanished. If a chromosome disappeared and production of a certain enzyme stopped, researchers knew the gene for that enzyme must be on the most recently vanished chromosome. Scientists in laboratories throughout North America and Europe began fusing cells and using them to map genetic traits to specific chromosomes, creating a precursor to the human genome map we have today. — Rebecca Skloot