Rap1 Proteins Role at Telomeres Solved

Mice and humans share numerous commonalities including their telomeres, the protective ends on chromosomes.  However, there is one particular protein, Rap1, at telomeres whose role has perplexed scientists for years. The Rap1 protein binds telomeres and then helps guard and maintain the telomere allowing the telomere to maintain its protective function. Previous research showed that in humans Rap1 played a crucial role while in mice the protein appeared to play only a minor role. This discrepancy was difficult to explain since both mice and humans are mammals.

New research at RockefellerUniversity has solved the discrepancy in the Rap1 protein. Researchers have discovered that the protein contributes very little if any to the protection of the telomere. However, while the research has solved the role of Rap1 in the protection of telomeres, another question was raised due to the research. This question is if Rap1 doesn’t protect telomeres why has evolution maintained the protein in both mice and humans?

Previous research has shown that dysfunctional telomeres have been linked to aging and cancer. Additionally, in prior research there were no changes in mice telomere length observed; however, mice have much longer telomeres so slight changes are more difficult to detect than they are in humans. Rap1 is one of six shelterin components in humans and mice, and dates back all the way back to yeast and a single-celled parasite called trypanosomes.

Shaheen Kabir, a graduate student in the lab, stated, “"We piled up a lot of negative data looking for effects of removing Rap1 from human telomeres. We observed no fusions, no significant changes in telomere length, no turning on of DNA damage signaling, the list goes on.”

The researchers concluded the possibility that Rap1 has a redundant function that overlaps with other shelterin components cannot be dismissed; however, it is most likely the protein must fill some other, unrelated role. Rap1 was first identified as a protein that turns genes on or off and research in mammalian cells have shown that the protein has a strong influence on genes related to body weight and metabolism which explains why evolution has maintained the protein.

This article was interesting because it discussed research that bought clarity to a previously unclear discrepancy. While the research does not provide anything groundbreaking it brings closer to an issue that has baffled scientists for decades and discoveries such as this are always important. 

Main Article: http://www.sciencedaily.com/releases/2014/11/141106132212.htm

Secondary Article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792482/

The choice between coffee or beer could have an effect on genome

         A study from the Tel Aviv University’s Department of Molecular Microbiology and Biotechnology reveals that coffee and beer may affect our genomes differently. Alcohol was found to lengthen and caffeine was found to shorten telomeres in yeast that is genetically similar to humans. Telomeres are located at the ends of DNA strands and are crucial to the correct repairing and copying of DNA strands. The yeast cells were exposed to twelve environmental stressors that did not affect telomere length, except for the presence of ethanol and caffeine. In the presence of 5-7% ethanol solution, the telomeres grew in length. In the presence of a small concentration of caffeine, the telomeres decreased in length. Rap1 and Rif1 were the two genes identified that were identified to play a role in environmental factors and telomere length. There are about 400 genes that play a role in telomere length, most of which are in humans. More work must be done to reveal if these factors will have the same effects on humans. The identification of a relationship between these environmental stressors and telomere length could lead to dietary guidelines and treatments.

            Another study of the effects of coffee consumption showed differing results. A study of older adults found that those who drank coffee saw decreased risk of death from diabetes, accidents, and injuries, respiratory disease, stroke, infections, and heart disease. The risk of death was 10% lower in those who consumed three of more cups a day than non- coffee drinkers.

            Coffee or beer? I found that the fact that the choice could affect our genomes to be rather interesting. As the leader of the study stated, this is the first time environmental factors that affect telomere length have been found. I did not realize that the discovery of the relationship between coffee or beer consumption and telomere length could be significant. Yet, it was brought to light that the relationship could be used in medical treatment. I am curious to see if the relationship will exist when the study is conducted for humans.

Primary Article: http://www.sciencedaily.com/releases/2013/12/131205142127.htm

Secondary Article: http://www.sciencedaily.com/releases/2012/05/120519071454.htm