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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 2
pubmed:dateCreated
1982-5-21
pubmed:abstractText
To study the effect of gene dosage on gene expression, lambda plac5cI857O29P3, a replication defective lambda phage carrying part of the lac operon (containing the lac promotor, operator and z gene) in the b2 region was studied in Escherichia coli strain JC6256 where the lac operon is deleted and at a temperature where the lambda repressor is inactive. In measuring the synthesis of beta-galactosidase, it was possible to separate the effects of the lac promoter from those of the phage promoter. When the synthesis of beta-galactosidase was initiated from the inserted lac promoter in JC6256(lambda +) in the presence of additional cyclic AMP, the rate and level of beta-galactosidase synthesis were directly proportional to the multiplicity of infection (gene dosage). Furthermore, beta-galactosidase synthesis was initiated about 5 min after infection, just as with isopropyl-beta-D-thiogalactoside (IPTG) induction. When the synthesis of beta-galactosidase was initiated from the phage promoter in JC6256 in the absence of additional cyclic AMP, the rate and level of beta-galactosidase synthesis were again linearly proportional to gene dosage. On the other hand, initiation of beta-galactosidase synthesis was delayed until 10 to 20 min after infection. These results suggest that: (i) in the absence of negative controlling factors, the extent of gene expression is proportional to gene dosage; (ii) varying the gene dosage can be used to regulate gene expression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-1317
pubmed:author
pubmed:issnType
Print
pubmed:volume
58
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
297-304
pubmed:dateRevised
2000-12-18
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Gene dosage as a regulatory factor for gene expression. I. In lambda plac5-infected cells.
pubmed:publicationType
Journal Article