Linked Life Data

9718316

Source:http://linkedlifedata.com/resource/pubmed/id/9718316

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
1998-9-14
pubmed:abstractText
We recently demonstrated that IFI 16, a human member of a family of interferon-inducible nuclear proteins, can function as a potent repressor of transcription. All members of this family are found in the nucleus and contain 1 or 2 copies of a conserved 200 amino acid repeat domain. IFI 16 migrates on SDS-PAGE as three distinct protein species (IFI 16A, 16B, 16C) clustered at 85-95 kDa, and we therefore set out to determine the molecular mechanisms underpinning the production of these different isoforms. In the present report, we have used thermal cycling amplification of reverse-transcribed mRNA (RT-PCR) and Southern blotting of genomic DNA to show that the three protein isoforms result from translation of three separate mRNA species produced by differential mRNA splicing. This differential splicing gives rise to variability in the central ("hinge") domain of the molecule which separates the two 200 amino acid repeats. The longest mRNA (approximately 2.7 kb) encodes an open reading frame of 2355 bp and generates the IFI 16A isoform of 785 amino acids. It contains sequences from 11 exons, including a newly identified exon (7a) which appears to have arisen by tandem duplication of exon 7. The second isoform (IFI 16B, corresponding to the form reported previously) is the most abundantly expressed, and results from deletion of exon 7a (168 bp) to encode a protein of 729 amino acids. The smallest mRNA encodes the IFI 16C isoform (2019 bp), has deleted both exon 7 and exon 7a, and shortens the protein by a further 56 amino acids. Culture of IFI 16-expressing cells with tunicamycin and incubation of cellular lysates with endoglycosidase H suggested that neither IFI 16A nor IFI 16B is glycosylated; however, some IFI 16C molecules showed a minor degree of complex carbohydrate addition. Furthermore, immunoprecipitation and Western blotting indicated that all three IFI 16 isoforms are phosphorylated on serine and threonine residues, but not on tyrosine. Thus, the three IFI 16 protein isoforms arise due to alternative RNA splicing and not due to differential glycosylation or phosphorylation. Finally, IFI 16 isoforms can homo- and heterodimerize, and we have mapped the dimerization domain to the amino terminus which contains an imperfect leucine zipper domain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11924-31
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:9718316-Alternative Splicing, pubmed-meshheading:9718316-Amino Acid Sequence, pubmed-meshheading:9718316-Base Sequence, pubmed-meshheading:9718316-DNA, Complementary, pubmed-meshheading:9718316-Dimerization, pubmed-meshheading:9718316-Exons, pubmed-meshheading:9718316-Gene Dosage, pubmed-meshheading:9718316-Glycosylation, pubmed-meshheading:9718316-HeLa Cells, pubmed-meshheading:9718316-Humans, pubmed-meshheading:9718316-Interferons, pubmed-meshheading:9718316-Isomerism, pubmed-meshheading:9718316-Molecular Sequence Data, pubmed-meshheading:9718316-Nuclear Proteins, pubmed-meshheading:9718316-Phosphoproteins, pubmed-meshheading:9718316-Phosphorylation, pubmed-meshheading:9718316-Proteins, pubmed-meshheading:9718316-RNA, Messenger, pubmed-meshheading:9718316-Repressor Proteins, pubmed-meshheading:9718316-Tumor Cells, Cultured
pubmed:year
1998
pubmed:articleTitle
Isotypic variants of the interferon-inducible transcriptional repressor IFI 16 arise through differential mRNA splicing.
pubmed:affiliation
The John Connell Laboratory, The Austin Research Institute, Heidelberg, Australia. r.johnstone@ari.unimelb.edu.au
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't