Monday, October 3, 2011

Gene found that is responsible for waking you up

A single gene, coding for a protein that is part of a mechanism involved with setting your internal clock, seems to be responsible for creating a biological wake up call. It was already known that humans have a biological clock that ticks with a certain rhythm. This is how we maintain our daily cycle. In a recent study, the gene KDM5A was found to be responsible for activating the internal circuit that makes us wake up from sleep, without an alarm clock. KDM5A codes for a protein called JARID1a, which functions as a biochemical switch that sets it all in motion. While the mechanism behind our daily, circadian rhythm was already known, it was not clear what gave the signal to start up our physiological functions.

Studying JARID1a might give us more insight in how our body sets our sleep-wake cycle. This can help us in unraveling how sleep disorders work. It may also allow us to modify our sleeping pattern, as modifying the activity of JARID1a, or its gene KDM5A, could change the time our body wants to wake us up.

Our internal clock resides in a brain area called the suprachiasmatic nucleus (SCN). Here, external input is relayed to the pineal gland deep inside the brain. This small organ is responsible for making melatonin, which is produced rhythmically, and is used to keep our biological clock functioning. Melatonin levels peak at night, while at day the production is significantly lowered. The daily rhythm by which the SCN signals to the pineal gland is built in, but can be modified by external input that enters the body through the eyes: light. Light is the most important factor for setting our daily rhythm. 

We do not only have an internal clock that regulates our sleep-wake cycles. There are many more clocks, taking care of various rhythmic functions. Secretion of hormones, blood pressure and muscle strength are factors that change rhythmically. The SCN not only signals to the pineal gland for the production of the 'sleep hormone' melatonine, but also produces various proteins involved with setting rhythmic behaviour: the so-called PER proteins have a role in, for example, varying the level of metabolism during day and night. However the SCN is considered as the 'master clock', there are also more clocks insider our bodies. Liver cells, for example, behave rhythmically in response to feeding, but there are clocks found in many organs, regulating various forms of behaviour.

A new drug that affects JARID1a would be welcome, as I'd like to be more of a morning person. 

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