Junk DNA: goodbye!: more lncRNC cell functions (Introduction)

by David Turell , Tuesday, December 27, 2016, 00:20 (2680 days ago) @ David Turell

The research continues to show 'junk' DNA is not junk. Another study into long non-coding RNA functions. Only 2% of DNA codes for protein, but a huge percentage of the remaining 98% does modulating function:

http://medicalxpress.com/news/2016-12-reveals-importance-non-coding-rna-cellular.html

"The investigators used computational analyses to predict potential polypeptides that could be encoded by known lncRNA molecules, and then they used mass spectrometry to determine if these putative polypeptides were actually expressed. "With this approach we actually identified many expressed hidden polypeptides and went on to characterize one in particular," Pandolfi explained. This specific lncRNA molecule is termed LINC00961 and encodes a 90 amino acid polypeptide.

"A variety of molecular and biochemical experiments revealed that the LINC00961 encoded polypeptide played an important role in modulating the activity of the mTORC1 protein complex, which is a critical sensor of nutrient availability within cells. The complex also regulates a variety of cellular processes including translation, metabolism, cell growth, and proliferation, and alterations in its function can lead to diseases such as cancer. Because the LINC00961 polypeptide appeared to specifically block mTORC1's ability to sense stimulation with amino acids, the investigators named the peptide encoded by the lncRNA SPAR (Small regulatory Polypeptide of Amino acid Response).

Pandolfi and his team found that the SPAR encoding lncRNA is highly expressed in a number of tissue types, including muscle. Experiments conducted in mice demonstrated that through its effects on mTORC1, the SPAR polypeptide helps regulate the muscle's ability to regenerate and repair after injury. Specifically, expression of LINC00961 is blocked following muscle injury in mice, leading to reduced levels of SPAR and maximal mTORC1 activity to promote tissue regeneration.

"The experimental approach we used allowed us to eliminate expression of the SPAR polypeptide, while maintaining expression of the host lncRNA," said lead author Akinobu Matsumoto, PhD, research fellow at the Cancer Center at BIDMC and lead author of the study. "We are able to ascribe this function to the coding function of the lncRNA rather than any non-coding function it may also have." The findings suggest that therapeutic strategies that restrict expression of SPAR in injured muscle may promote a more rapid regeneration of tissue.

"The results suggest that lncRNAs may have diverse roles and functions. Although they may not code for large proteins, lncRNAs may produce small polypeptides that can fine tune the activity of critical cellular components. The findings also expand the repertoire of peptide-coding genes in the human genome that should be studied and annotated.

"The study also provides insights on how mTORC1 activity may be attuned to meet the distinct needs of a specific tissue. "An ability to target such modulators could be of great advantage from a therapeutic perspective, allowing for control of mTORC1 activity in cells or tissues that express such modulators while not affecting its activity and function in other tissue and cell types," explained co-author John Clohessy, PhD, Instructor in Medicine at BIDMC and a senior member of Pandolfi's research team. Indeed, a key feature of many lncRNAs is that their expression is often highly tissue-specific. Thus, targeting small polypeptides encoded by lncRNA molecules may provide the key to regulating common cellular components in a tissue-specific manner."

Comment: It is obvious that DNA is changed to be tissue specific and organ specific in the cells in the liver, in the kidney, in the lung, etc. lncRNA is one of the results. It is obvious that the function of DNA must be production of protein, but that simply creates the structures of life. DNA must also be able to also manage the functions of life through modifiers.