Sunday, 28 February 2010

GATA-1: A Protein That Regulates Proteins

Proteins are the cell’s special machines that perform a variety of tasks. Some of them help to regulate the production levels of other proteins by influencing the transcribing of the DNA genes that code for the proteins. New research is investigating how one such transcription factor, GATA-1, works and, as usual, it isn’t simple.

Looking at baby red blood cells in mice, the research found the genes that GATA-1 influences are positioned together along the DNA molecule. GATA-1 binds to specific locations along the DNA molecule and genes that cluster around those locations tend to be induced or repressed by the binding of GATA-1. Genes not in these clusters are relatively unaffected. So if GATA-1 is to influence the production of certain proteins, then the corresponding genes need to be positioned in these regulatory clusters.

But why are some genes induced while others are repressed? One factor is how close the gene is to the GATA-1 protein. The closer genes tend to be induced whereas the more distant genes tend to be repressed. So the positioning of the genes is even more fine-tuned. Not only are the genes to be influenced found in the regulatory clusters, but their position within the cluster is important.

There are other factors as well. For instance, TAL1 is another transcription factor and when it is absent the nearby genes are usually repressed. This is usually accompanied by a modification of one of the histone proteins around which the DNA is wrapped. Specifically, the 27th amino acid in histone H3, a lysine, is trimethylated (three methyl groups are added to the side chain).

These and other factors help to explain how GATA-1 works to regulate protein production, and why some genes are induced while others repressed. But the observed factors do not fully explain the patterns of protein production. For instance, many repressed genes do not lack the TAL1 transcription factor. There is still more to be learned.

Evolutionists believe these protein regulation mechanisms and factors arose from molecular mishaps that were passed on. Those mishaps that luckily helped out persisted. The gene positionings, GATA-1 design, production and binding sites, TAL1, histone trimethylation machine, and other intricacies just happened to arise by happenstance. And they worked. Religion drives science and it matters.