Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

The most well studied genetic oscillators in human genomes are involved in regulating the circadian clock (which operates on an approximately 24-hour cycle) and cell cycle activity (with single cycles usually lasting several hours to many days). Are there any known genetic oscillators in humans (or other mammals) that operate on shorter timescales?

share|improve this question
    
Many mammalian cells (or cell lines) have cell cycle period < 24hours. What timescale are you interested in. Usually it takes few hours for proteins to achieve steady states. –  WYSIWYG Jul 21 at 8:12
    
I'm looking for an example where oscillations occur within hours and are not coupled to the cell cycle. Thanks! –  yummyclaypot Jul 21 at 14:34
    
Natural or synthetic ? –  WYSIWYG Jul 22 at 5:16
    
Natural, and the simpler (fewer parts) the better. I'm looking for an endogenous oscillator that can be coupled to synthetic circuits. –  yummyclaypot Jul 22 at 6:18

1 Answer 1

up vote 5 down vote accepted

Here are some examples:

  • electric oscillators:
  • mechanical oscillators (as a result of neural activity):
    • heart beats
    • breathing (0.2 ... 0.3 Hz)
    • intestinal peristaltic waves
    • vocal chords activity (up to a few kHz)
    • muscular spasm (pathological)
  • chemical oscillators:
    • insulin variation in concordance with glucose intake
    • endocrine oscillations
    • menstruation
    • feedback enabled metabolic pathways

See this Wikipedia page too: http://en.wikipedia.org/wiki/Oscillation#Human

When it comes to genetic oscillators, some of them follow circadian rhythm.

A typical proliferating human cell divides on average every 24 h. This division timing allows cells to synchronize with other physiological processes and with the environment. The circadian clock, which orchestrates daily rhythms, directly regulates the cell division cycle and is a major synchronizing factor [5].

Immune system:

In every single cell an oscillator goes ticking through a molecular clock operated by transcriptional/translational feedback loops driven by the rhythmic expression of circadian genes. This clock gene machinery steers daily oscillations in the regulation of immune cell activity, driving the periodicity in immune system function [1].

Glucose homeostasis:

The master circadian clock, localized in suprachiasmatic nucleus (SCN), regulates multiple metabolic pathways, while feeding behavior and metabolite availability can in turn regulate the circadian clock [2].

Retina:

... the retina itself possesses intrinsic circadian oscillations, exemplified by diurnal fluctuations in visual sensitivity, neurotransmitter levels, and outer segment turnover rates. Recently, it has been noted that both central and peripheral oscillators share a molecular clock consisting of an endogenous, circadian-driven, transcription-translation feedback loop that cycles with a periodicity of approximately 24 hours [3].

But there are others which don't.

Genetic oscillators are ubiquitous regulatory motifs in the molecular control circuits of living cells. Prominent examples include the cell cycle and cellular signaling [4].

The frequency is much lower in some human cells [6]:

Cell Type      Process    Time
______________ __________ ______________________
fly embryo     mitosis    8 minutes
bacteria       mitosis    20 minutes
yeast          mitosis    2 hours
human skin     mitosis    20 - 24 hours
human sperm    meiosis    about 64 days
human liver    mitosis    1 year or more
human egg      meiosis    up to 40 years or more
human nerve    mitosis    never, once mature

References:

  1. Vinciguerra M, Borghesan M, Pazienza V, Piepoli A, Palmieri O, Tarquini R, Tevy MF, De Cata A, Mazzoccoli G. The transcriptional regulators, the immune system and the the circadian clock. J. Biol. Regul. Homeost. Agents. 2013;27(1):9-22. PubMed PMID: 23489683.
  2. Chrościcki P, Usarek M, Bryla J. [The role of biological clock in glucose homeostasis]. Postepy Hig Med Dosw (Online). 2013 Jun 20;67:569-83. doi: 10.5604/17322693.1053906. PubMed PMID: 23799401.
  3. Ramsey DJ, Ramsey KM, Vavvas DG. Genetic advances in ophthalmology: the role of melanopsin-expressing, intrinsically photosensitive retinal ganglion cells in the circadian organization of the visual system. Semin Ophthalmol. 2013 Sep 6;28(5-6):406-21. doi: 10.3109/08820538.2013.825294. PubMed PMID: 24010846.
  4. Davit A. Potoyan and Peter G. Wolynes. On the dephasing of genetic oscillators. PNAS 2014 ; published ahead of print January 27, 2014, doi:10.1073/pnas.1323433111
  5. Samuel Bernard and Hanspeter Herzel. Why Do Cells Cycle with a 24 Hour Period? Genome Informatics 17(1): 72{79 (2006).
  6. wiseGEEK.org. How Long Does it Take for Cells to Divide? (accessed 21.07.2014)
share|improve this answer
    
Great list! Thanks! Sorry, I was too vague in my question. I've edited it to refer specifically to 'genetic' oscillation. Do you have an example of a 'feedback enabled metabolic pathway' where high frequency oscillations depend on RNA/protein expression and degradation? Sorry for the confusion. –  yummyclaypot Jul 20 at 20:59
    
Thanks! This is a solid answer. Reference 4 is especially helpful. –  yummyclaypot Jul 21 at 14:40

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.