Basic Description

Autoradiography can be used to image tissues, cells or components of cells that have been labeled with radioactive isotopes. X-ray film or other photographic emulsions, which are sensitive to the radioactive decay emissions from the sample, are used to produce an image (autoradiograph). The sample itself contains the source of the radiation, which differentiates this technique from radiography, where the source of the radiation is outside of the sample. (Grounds)

Purpose

Autoradiography has several applications in the realm of cellular physiology. It can be used to track a certain reaction or molecular pathway by putting the sample in an environment where it will take in a radioisotope. Images taken at different times then show the progress of the radioisotope through a specific pathway. The technique can also be used to see where specific components are located in a cell or tissue, by “pulsing” the sample with a short burst of radioactive compound. (Alberts et al. 601 - 602)

History and Origins

The precursors of autoradiography were experiments performed in the late 1800's, when several scientists saw darkening of various materials which had come in contact with uranium nitrate. The modern technique was first used in the 1940's and 1950's, when 131I was traced in thyroid sections. The technique was refined and expanded throughout the following years. Currently, there are many radioisotopes and other radioactive compounds available for use in autoradiography. (Introduction to Autoradiography: History)

Recent Research

In “Tracking Monolignols during Wood Development in Lodgepole Pine”, autoradiography allowed the researchers to investigate the exportation of monolignols (substances that provide materials for the production of lignans and lignins). It showed that monolignols are not transported by a Golgi-vesicle system, as was earlier suspected, as the monolignols did not concentrate in the ER or Golgi apparatus. (Kaneda et al.) In “An Insulin-Like Peptide Regulates Egg Maturation and Metabolism in the Mosquito Aedes aegypti”, autoradiography was used to examine how bovine insulin reacted with mosquito insulin receptors (MIR), in order to see whether mammalian (bovine) insulin could stimulate egg maturation in the mosquitoes. The technique allowed the researchers to see if the insulin was actually interacting with the MIR, and to what degree. It was determined that an insulin-like peptide, ILP3, was a regulator of egg production in the mosquitoes. (Brown et al.) In “Human Mitochondrial RNA Polymerase Primes Lagging-Strand DNA Synthesis in vitro”, researchers used autoradiography to examine the results of various electrophoresis experiments. Their results lead the researchers to suggest that mitochondrial RNA polymerase is the lagging-strand primase in mammalian mitochondria. (Wanrooij et al.)

References

Alberts, Bruce, Alexander Johnson, et al. Molecular Biology of The Cell. 5th ed. New York: Garland Science, 2008. 601-602. Print.

Brown, Mark R., Kevin D. Clark, et al. "An Insulin-Like Peptide Regulates Egg Maturation and Metabolism in the Mosquito Aedes aegypti." Proceedings of the National Academy of Sciences of the United States of America. 105.15 (2008): 5716-5721. Web. 14 Oct. 2012. <http://www.jstor.org/stable/25461675>.

Grounds, Miranda. "Autoradiography." The University of Western Australia. N.p., 01 2006. Web. 14 Oct 2012 <http://www.lab.anhb.uwa.edu.au/hb313/main_pages/timetable/lectures/autoradiography.htm>.

"Introduction to Autoradiography: History." Universiteit Gent. N.p.. Web. 14 Oct 2012. <http://www.analchem.ugent.be/radiochemie/autoradiografie/autoradiography/intro_hist.html>.

Kaneda, Minako, Kim H. Rensing, et al. "Tracking Monolignols during Wood Development in Lodgepole Pine." Plant Physiology. 147.4 (2008): 1750 - 1760. Web. 14 Oct. 2012. <http://www.jstor.org/stable/40066113>.

Wanrooij, Sjoerd, Javier Miralles Fuste, et al. "Human Mitochondrial RNA Polymerase Primes Lagging-Strand DNA Synthesis in vitro." Proceedings of the National Academy of Sciences of the United States of America. 105.32 (2008): 11122 - 11127. Web. 14 Oct. 2012. <http://www.jstor.org/stable/25463303>.