Squid Doryteuthis pealeii is capable of changing the sequence of nucleotides in RNA not only in the nuclei of cells, but also in axons — the long processes of neurons that carry nerve impulses. Moreover, axons of this process is more intense than in the bodies cells. Probably, this allows the molluscs to implement a very fine tuning of the nervous system. Article published in Nucleic Acids Research.
Genes encode proteins, but information about the sequence of amino acids in proteins is not taken directly with DNA and RNA. You can read information from one area of DNA to create a multiple copies of the RNA, and then slightly change each of them so that they do not coincide with each other. Then, when these RNAS fall into the ribosome, they will produce different protein molecules. This allows us to expand the variety of proteins that can synthesize a cell, however, leave unchanged the genetic information.
To change the sequence of nucleotides in RNA of the organisms that have the enzyme from the group adenosinedeaminaseacting on RNA (ADAR). They convert adenosine to inosine is the nucleoside, closer to the guanosine. As a result, the ribosome reads the other information from RNA and protein constructs with altered amino acid sequence. ADAR have many animals, including people, but not all RNA are areas which could be contacted by this enzyme.
The exception of cephalopods. In some species nearly half of the RNA can be recoded with the help of ADAR. RNA, which turns out to be altered, often are synthesized in the nerve cells. Adenozindezaminaza gives the neurons more efficient in low temperatures, but surely there are other biological sense of the recoding of RNA in nerve cells.
The staff of the Laboratory of marine biology, University of Chicago, together with colleagues from the University of Colorado in Denver and tel Aviv University, headed by Joshua Rosenthal (Joshua Rosenthal) have long been studying recoding RNA in the neurons of cephalopods. Their earlier research was focused on changes in ribonucleic acids in the nuclei of nerve cells. In the new work, they decided to see if adenozindezaminaza act on RNA outside nucleus.
To test this, the researchers used the squid Doryteuthis pealeii. In the 1930-ies of Alan Hodgkin and Andrew Huxley established a mechanism for transmission of nerve impulses aksonam (the long processes of neurons) of the same shellfish. Now biologists using Western blotting, immunohistochemistry and transcriptomic identified in any tissues of the squid ADAR is present and what is the percentage of substitutions of adenosine to inosine in different parts of the body and even individual cells of the animal.