9 Comments

Tal­mu­dic Ques­tion #92

Does DNA do any­thing other than serve as a repos­i­tory for ge­netic in­for­ma­tion?

 

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Mark Silby
13 years ago

Isn't there some pretty nice work show­ing DNA to be a struc­tural com­po­nent in some biofilms?

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Johan Laserna
13 years ago

It also serves as a tempt­ing ex­plana­tory gad­get, sat­is­fy­ing our es­sen­tial­is­tic be­liefs about causal­ity, in­ten­tions and the liv­ing. Of which, it is seems, quite un­aware.

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barry
13 years ago

of course! its a cen­tral bul­letin board for keep­ing track of what's go­ing on in the cell:
1) the cell 'knows' what state it is in by the col­lec­tion of pro­teins bonded to the con­trol se­quences for each gene
2) tran­scrip­tion com­plexes look at this bul­letin board to see which genes should be ex­pressed at any given time

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barry
13 years ago

oh. and when bac­te­ria are send­ing plas­mids to each other, DNA is also act­ing as a sig­nal mol­e­cule, on some level. no?

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James H.
13 years ago

There are hints in the large lit­er­a­ture that has es­tab­lished DNA as a struc­tural and dif­fu­sion-lim­it­ing part of some biofilms that it may be pro­duced or re­leased in a man­ner dif­fer­ent from sim­ple cell ly­sis, and may not have the same com­po­si­tion as the ge­nomic DNA (see DOI: 10.1111/j.1574–6968.2006.00361.x).
Also, DNA is a car­bon and en­ergy source (as well as pro­vid­ing P and N) for some mi­crobes. The up­take of poly­meric DNA as a sub­strate for growth is pos­si­bly in­volved in the de­vel­op­ment of nat­ural com­pe­tence (for ex­am­ple, DOI: 10.1128/​AEM.02674–06).
DNA can act as a con­duc­tor for elec­trons. Given the re­cent work on bac­te­r­ial nano-wires, are there any re­ports of con­juga­tive pili or other DNA struc­tures used to trans­fer elec­trons?

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Tim
13 years ago

One could ar­gue that DNA is also a sig­nalling mol­e­cule, par­tic­u­larly for eu­kary­otic in­nate im­mune re­sponses.
Not to men­tion its role in neu­trophil ex­tra­cel­lu­lar traps to wrap up mi­crobes!

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Mark O. Martin
13 years ago

Mark, in­deed. A great pa­per from 2002. Nice and short and to the point! A real MPU (min­i­mal pub­lish­able unit), which is great for ed­u­ca­tors to show their stu­dents...
http://www.sciencemag.org/content/295/5559/1487.citation

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Moshe Harel
13 years ago

Kill bac­te­ria in eu­kary­otic sys­tems.
Cell Death Dif­fer. 2011 Apr;18(4):581–8.
Dy­ing for a cause: NE­To­sis, mech­a­nisms be­hind an an­timi­cro­bial cell death modal­ity.
Ab­stract
Neu­trophil ex­tra­cel­lu­lar traps (NETs) are chro­matin struc­tures loaded with an­timi­cro­bial mol­e­cules. They can trap and kill var­i­ous bac­te­r­ial, fun­gal and pro­to­zoal pathogens, and their re­lease is one of the first lines of de­fense against pathogens. In vivo, NETs are re­leased dur­ing a form of pathogen-in­duced cell death, which was re­cently named NE­To­sis. Ex vivo, both dead and vi­able neu­trophils can be stim­u­lated to re­lease NETs com­posed of ei­ther nu­clear or mi­to­chon­dr­ial chro­matin, re­spec­tively. In cer­tain patho­log­i­cal con­di­tions, NETs are as­so­ci­ated with se­vere tis­sue dam­age or cer­tain auto-im­mune dis­eases. This re­view de­scribes the re­cent progress made in the iden­ti­fi­ca­tion of the mech­a­nisms in­volved in NE­To­sis and dis­cusses its in­ter­play with au­tophagy and apop­to­sis.
Elio, what is your opin­ion on the sub­ject?!

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Mike jones
13 years ago

I haven't started to look this up yet, but what role does DNA (or RNAs) have in pH bal­ance in the cell and as a sink for ions? All those phos­phate groups must have a sig­nif­i­cant buffer­ing ca­pac­ity on a mi­croscale. At this year's Cana­dian so­ci­ety of mi­cro­bi­ol­ogy meet­ing, there was an ex­cel­lent talk about the chelat­ing abil­ity of DNA; im­pli­cated in its ef­fec­tive­ness as NETs (the pre­vi­ously men­tioned neu­trophilic ex­tra­cel­lu­lar DNA). Could cells be bal­anc­ing out their salts with their DNA?

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