Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity.
Lactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analy...
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doaj-7c277568403048f6b1fb2982213571e92020-11-24T21:45:07ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0191e8387610.1371/journal.pone.0083876Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity.Masahiro ItoYun-Gi KimHirokazu TsujiTakuya TakahashiMayumi KiwakiKoji NomotoHirofumi DanbaraNobuhiko OkadaLactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analyses identified three independent genes that were disrupted by insertion of the transposon element: asnH, encoding asparagine synthetase, and dnaJ and dnaK, encoding the molecular chaperones DnaJ and DnaK, respectively. Using an in vivo mouse model of Listeria infection, only asnH mutant showed deficiency in their ability to enhance host innate immunity, and complementation of the mutation by introduction of the wild-type asnH in the mutant strain recovered the immuno-augmenting activity. AsnH protein exhibited asparagine synthetase activity when the lysozyme-treated cell wall extracts of L. casei ATCC 27139 was added as substrate. The asnH mutants lost the thick and rigid peptidoglycan features that are characteristic to the wild-type cells, indicating that AsnH of L. casei is involved in peptidoglycan biosynthesis. These results indicate that asnH is required for the construction of the peptidoglycan composition involved in the immune-activating capacity of L. casei ATCC 27139.http://europepmc.org/articles/PMC3885529?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Masahiro Ito Yun-Gi Kim Hirokazu Tsuji Takuya Takahashi Mayumi Kiwaki Koji Nomoto Hirofumi Danbara Nobuhiko Okada |
spellingShingle |
Masahiro Ito Yun-Gi Kim Hirokazu Tsuji Takuya Takahashi Mayumi Kiwaki Koji Nomoto Hirofumi Danbara Nobuhiko Okada Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. PLoS ONE |
author_facet |
Masahiro Ito Yun-Gi Kim Hirokazu Tsuji Takuya Takahashi Mayumi Kiwaki Koji Nomoto Hirofumi Danbara Nobuhiko Okada |
author_sort |
Masahiro Ito |
title |
Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. |
title_short |
Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. |
title_full |
Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. |
title_fullStr |
Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. |
title_full_unstemmed |
Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. |
title_sort |
transposon mutagenesis of probiotic lactobacillus casei identifies asnh, an asparagine synthetase gene involved in its immune-activating capacity. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2014-01-01 |
description |
Lactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analyses identified three independent genes that were disrupted by insertion of the transposon element: asnH, encoding asparagine synthetase, and dnaJ and dnaK, encoding the molecular chaperones DnaJ and DnaK, respectively. Using an in vivo mouse model of Listeria infection, only asnH mutant showed deficiency in their ability to enhance host innate immunity, and complementation of the mutation by introduction of the wild-type asnH in the mutant strain recovered the immuno-augmenting activity. AsnH protein exhibited asparagine synthetase activity when the lysozyme-treated cell wall extracts of L. casei ATCC 27139 was added as substrate. The asnH mutants lost the thick and rigid peptidoglycan features that are characteristic to the wild-type cells, indicating that AsnH of L. casei is involved in peptidoglycan biosynthesis. These results indicate that asnH is required for the construction of the peptidoglycan composition involved in the immune-activating capacity of L. casei ATCC 27139. |
url |
http://europepmc.org/articles/PMC3885529?pdf=render |
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