Linked Life Data

2760929

Source:http://linkedlifedata.com/resource/pubmed/id/2760929

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1989-9-18
pubmed:abstractText
The immunity region of the lambdoid phage, HK022, has been sequenced. The HK022 repressor gene, its cognate operators and promoters, and several early phage genes can be discerned. The overall design of the immunity region resembles that of other lambdoid phages. The location of the HK022 nun gene, whose product excludes superinfecting lambda by terminating transcription at (or near) the lambda nut sites, is analogous to that of gene N in lambda. nun is preceded by sequences similar to the lambda nut sites and the lambda pL promoter and is followed by several transcription termination signals. Despite these similarities, Nun is required neither for the lytic nor the lysogenic pathway of phage development. Again, unlike N, Nun is expressed in a prophage, perhaps from a promoter other than pL. We suggest that Nun and N have diverged in evolution and now perform different functions for their respective phages. Although Nun and N compete at the lambda nut sites and interact with the same host Nus proteins, they are only distantly related in predicted amino acid sequence. The presence of transcription terminators in the pL operon suggests that the expression of the HK022 early functions, like those of lambda, entails an antitermination mechanism. However, Nun does not appear to be an essential component of this mechanism. Our most economic model is that the HK022 nutL sequence suppresses pL operon terminators in the absence of a phage-encoded antitermination protein. Striking homologies between the HK022 nutL sequence and related sequences in the Escherichia coli rrn operons support this notion. Alternatively, a phage antitermination gene may be located outside the pL operon.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
207
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
675-93
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Structure and function of the nun gene and the immunity region of the lambdoid phage HK022.
pubmed:affiliation
Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, Bethesda, MD 20892.
pubmed:publicationType
Journal Article