Abstract：
:The hok/sok locus of plasmid R1 mediates plasmid stabilization by the killing of plasmid-free cells. Many bacterial plasmids carry similar loci. For example, the F plasmid carries two hok homologues, flm and srnB, that mediate plasmid stabilization by this specialized type of programmed cell death. Here, we show that the chromosome of E. coli K-12 codes for five hok homologous loci, all of which specify Hok-like toxins. Three of the loci appear to be inactivated by the insertion elements IS150 or IS186 located close to but not in the toxin-encoding reading frames (i.e. hokA, hokC and hokE), one system is probably inactivated by point mutation (hokB), whereas the fifth system is inactivated by a major genetic rearrangement (hokD). In the ECOR collection of wild-type E. coli strains, we identified hokA and hokC loci without IS elements. A molecular and a genetic analysis show that the hokA and hokC loci specify unstable antisense RNAs and stable toxin-encoding mRNAs that are processed at their 3' ends. An alignment of the mRNA sequences reveals all the regulatory elements known to be required for correct folding and refolding of the plasmid-encoded mRNAs. The conserved elements include fbi that ensure a long-range interaction in the full-length mRNAs, and tac and antisense RNA target stem-loops that are required for translation and rapid antisense RNA binding of the processed mRNAs. Consistently, we find that the chromosome-encoded mRNAs are processed at their 3' ends, resulting in the presumed translationally active mRNAs. Despite the presence of all of the regulatory elements, the chromosome-encoded loci do not mediate plasmid stabilization by killing of plasmid-free cells. The chromosome-encoded mRNAs are poorly translated in vitro, thus yielding an explanation for the lacking phenotype. These observations suggest that the chromosomal hok-like genes may be induced by an as yet unknown signal.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Pedersen K,Gerdes Kdoi
10.1046/j.1365-2958.1999.01431.xsubject
Has Abstractpub_date
1999-06-01 00:00:00pages
1090-102issue
5eissn
0950-382Xissn
1365-2958journal_volume
32pub_type
杂志文章abstract：:Cholesterol catabolism is widespread in actinobacteria and is critical for Mycobacterium tuberculosis (Mtb) virulence. Catabolism of steroid nucleus rings C and D is poorly understood: it is initiated by the CoA thioesterification of 3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP) by FadD3, whose gen...
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journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1995.tb02397.x
更新日期：1995-04-01 00:00:00
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pub_type： 评论,杂志文章
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更新日期：2012-09-01 00:00:00
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journal_title：Molecular microbiology
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pub_type： 杂志文章
doi：10.1111/mmi.12499
更新日期：2014-02-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1995.mmi_17010137.x
更新日期：1995-07-01 00:00:00
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更新日期：2019-09-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1998.01085.x
更新日期：1998-11-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1996.tb02648.x
更新日期：1996-06-01 00:00:00
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pub_type： 杂志文章,评审
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更新日期：1998-01-01 00:00:00
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更新日期：2004-06-01 00:00:00
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更新日期：2011-12-01 00:00:00
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pub_type： 杂志文章
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pub_type： 杂志文章,评审
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更新日期：2020-03-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
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更新日期：2003-10-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
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更新日期：1997-08-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
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更新日期：2006-03-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2006.05357.x
更新日期：2006-10-01 00:00:00
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journal_title：Molecular microbiology
pub_type： 杂志文章,评审
doi：10.1111/mmi.12697
更新日期：2014-08-01 00:00:00
