{{Short description|Antimicrobial peptide immune gene of fruit flies}}
{{Infobox nonhuman protein |image=|caption= |Symbol=Bara |UniProt=C0HLZ9 |Organism=Drosophila melanogaster }}
'''''Baramicin''''' (''Bara'') is an antimicrobial peptide gene of the fruit fly ''Drosophila melanogaster''. Baramicin is a prominent element of the fly immune response: of the most abundant immune peptides detected in the fly hemolymph, the ''[http://flybase.org/reports/FBgn0288447.html BaraA]'' gene is responsible for 9 of the 24 peptides first described for their high concentrations after systemic infection.<ref name = Utt1998>{{cite journal | vauthors = Uttenweiler-Joseph S, Moniatte M, Lagueux M, Van Dorsselaer A, Hoffmann JA, Bulet P | title = Differential display of peptides induced during the immune response of Drosophila: a matrix-assisted laser desorption ionization time-of-flight mass spectrometry study | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 95 | issue = 19 | pages = 11342–11347 | date = September 1998 | pmid = 9736738 | pmc = 21644 | doi = 10.1073/pnas.95.19.11342 | doi-access = free | bibcode = 1998PNAS...9511342U }}</ref><ref name = Levy2004>{{cite journal | vauthors = Levy F, Rabel D, Charlet M, Bulet P, Hoffmann JA, Ehret-Sabatier L | title = Peptidomic and proteomic analyses of the systemic immune response of Drosophila | journal = Biochimie | volume = 86 | issue = 9–10 | pages = 607–616 | date = September 2004 | pmid = 15556270 | doi = 10.1016/j.biochi.2004.07.007 }}</ref><ref name = Han2021>{{cite journal | vauthors = Hanson MA, Cohen LB, Marra A, Iatsenko I, Wasserman SA, Lemaitre B | title = The Drosophila Baramicin polypeptide gene protects against fungal infection | journal = PLOS Pathogens | volume = 17 | issue = 8 | article-number = e1009846 | date = August 2021 | pmid = 34432851 | pmc = 8423362 | doi = 10.1371/journal.ppat.1009846 | doi-access = free }}</ref>
==Etymology==
The name of the ''Baramicin'' gene was inspired by One Piece character "Buggy" and derives from the Japanese expression "Bara Bara", an onomatopoeia for things breaking apart, in reference to the Baramicin precursor breaking into multiple sub-peptides.<ref name = Han2021/>
== Activity ==
The Baramicin A precursor protein can be broken into three distinct domains: the '''IM10-like''', '''IM22''', and '''IM24''' domains. Five sub-peptides are produced by the BaraA precursor including one IM24 peptide, three IM10-like peptides, and one IM22 peptide.<ref name = Han2021/>
=== Immune response ===
The ''Baramicin'' gene is part of the Toll pathway antifungal immune response.<ref name = Utt1998/><ref name = Levy2004/> Flies lacking ''BaraA'' genetically are susceptible to infection by entomopathogenic fungi such as ''Beauveria bassiana'' and ''Metarhizium'' species, but also show some susceptibility to ''Enterococcus faecalis'' bacterial infection.<ref name="Han2021" /><ref name=":0">{{Cite journal |last1=Huang |first1=Jianqiong |last2=Lou |first2=Yanyan |last3=Liu |first3=Jiyong |last4=Bulet |first4=Philippe |last5=Cai |first5=Chuping |last6=Ma |first6=Kaiyu |last7=Jiao |first7=Renjie |last8=Hoffmann |first8=Jules A. |last9=Liégeois |first9=Samuel |last10=Li |first10=Zi |last11=Ferrandon |first11=Dominique |date=2023-03-21 |title=A Toll pathway effector protects Drosophila specifically from distinct toxins secreted by a fungus or a bacterium |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=12 |article-number=e2205140120 |doi=10.1073/pnas.2205140120 |issn=0027-8424 |pmc=10041126 |pmid=36917667|bibcode=2023PNAS..12005140H }}</ref> The IM10-like peptides of BaraA are specifically proposed as antifungal peptides produced by the ''BaraA'' gene.<ref name = Han2021/> The potential activity of the IM22 and IM24 peptides is unknown. Some element of the Baramicin protein may also regulate a behavioural response after infection, as flies lacking ''Baramicin'' display an erect wing phenotype after immune activation.<ref name = Han2021/>
=== Nervous system ===
Antimicrobial peptides and neuropeptides share many common features.<ref>{{cite journal | vauthors = Brogden KA, Guthmiller JM, Salzet M, Zasloff M | title = The nervous system and innate immunity: the neuropeptide connection | journal = Nature Immunology | volume = 6 | issue = 6 | pages = 558–564 | date = June 2005 | pmid = 15908937 | doi = 10.1038/ni1209 | s2cid = 33329267 | url = https://hal.archives-ouvertes.fr/hal-00167313/file/Natue_Immunol.pdf }}</ref> The distinction between which of these two roles, if either, is the primary function of any given peptide is often unclear.<ref>{{cite journal | vauthors = Zasloff M | title = An ancient neuropeptide defends the brain against infection | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 5 | article-number = e2023990118 | date = February 2021 | pmid = 33436393 | pmc = 7865180 | doi = 10.1073/pnas.2023990118 | doi-access = free | bibcode = 2021PNAS..11823990Z }}</ref><ref>{{cite journal | vauthors = Klimovich A, Giacomello S, Björklund Å, Faure L, Kaucka M, Giez C, Murillo-Rincon AP, Matt AS, Willoweit-Ohl D, Crupi G, de Anda J, Wong GC, D'Amato M, Adameyko I, Bosch TC | display-authors = 6 | title = Prototypical pacemaker neurons interact with the resident microbiota | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 117 | issue = 30 | pages = 17854–17863 | date = July 2020 | pmid = 32647059 | pmc = 7395494 | doi = 10.1073/pnas.1920469117 | doi-access = free | bibcode = 2020PNAS..11717854K }}</ref> The ''Baramicin'' gene family of ''D. melanogaster'' includes the immune-induced ''BaraA'' and also two non-immune ''Baramicin'' genes ''BaraB'' and ''BaraC''. The ''BaraB'' and ''BaraC'' genes are expressed in the nervous system, in neurons or glia respectively. Evolutionary study suggests the IM24 domain is the key element of the Baramicin precursor that is involved in Baramicin function in the nervous system. This finding suggests antimicrobial peptides and neuropeptides might accomplish immune or neural roles not only by dual action of a single peptide, but rather by different mechanisms of action of sub-peptides.<ref>{{cite journal |vauthors=Hanson MA, Lemaitre B |date=June 2022 |title=Repeated truncation of a modular antimicrobial peptide gene for neural context |journal=PLOS Genetics |volume=18 |issue=6 |article-number=e1010259 |doi=10.1371/journal.pgen.1010259 |pmc=9246212 |pmid=35714143 |doi-access=free }}</ref>
''BaraA'' mutants also display a reduced recovery rate after the injection of neurotoxins, which is rescued somewhat by expressing ''BaraA'' in glial cells of the fly's nervous system.<ref name=":0">{{Cite journal |last1=Huang |first1=Jianqiong |last2=Lou |first2=Yanyan |last3=Liu |first3=Jiyong |last4=Bulet |first4=Philippe |last5=Cai |first5=Chuping |last6=Ma |first6=Kaiyu |last7=Jiao |first7=Renjie |last8=Hoffmann |first8=Jules A. |last9=Liégeois |first9=Samuel |last10=Li |first10=Zi |last11=Ferrandon |first11=Dominique |date=2023-03-21 |title=A Toll pathway effector protects Drosophila specifically from distinct toxins secreted by a fungus or a bacterium |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=12 |article-number=e2205140120 |doi=10.1073/pnas.2205140120 |issn=0027-8424 |pmc=10041126 |pmid=36917667|bibcode=2023PNAS..12005140H }}</ref> Together with the description of antifungal activity of IM10-like peptides,<ref name="Han2021" /> the ''BaraA'' gene therefore encodes both immune antimicrobials and some factor that promotes host resilience in the face of microbial toxins.<ref name=":0" />
== References == {{reflist}}
== Further reading == * FlyBase BaraA: http://flybase.org/reports/FBgn0288447 * FlyBase BaraB: http://flybase.org/reports/FBgn0033353 * FlyBase BaraC: http://flybase.org/reports/FBgn0050285
Category:Peptides Category:Antifungals