Change search
ReferencesLink to record
Permanent link

Direct link
The evolutionarily conserved single-copy gene for murine Tpr encodes one prevalent isoform in somatic cells and lacks paralogs in higher eukaryotes.
Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.ORCID iD: 0000-0003-3492-3287
Show others and affiliations
2002 (English)In: Chromosoma, ISSN 0009-5915, E-ISSN 1432-0886, Vol. 111, no 4, 236-255 p.Article in journal (Refereed) Published
Abstract [en]

Vertebrate Tpr and its probable homologs in insects and yeast are heptad repeat-dominated nuclear proteins of M(r) 195,000 to M(r) 267,000 the functions of which are still largely unknown. Whereas two homologs exist in Saccharomyces cerevisiae, it has remained uncertain whether metazoans possess different paralogs or isoforms of Tpr that might explain controversial reports on the subcellular localization of this protein. To address these possibilities, we first determined the sequence and structure of the murine tpr gene, revealing a TATA box-less gene of approximately 57 kb and 52 exons. Southern hybridization of genomic DNA and radiation hybrid mapping showed that murine tpr exists as a single-copy gene on chromosome 1; RNA blotting analyses and EST (expressed sequence tag) database mining revealed that its expression results in only one major mRNA in embryonic and most adult tissues. Accordingly, novel antibodies against the N- and C-terminus of Tpr identified the full-length protein as the major translation product in different somatic cell types; reinvestigation of Tpr localization by confocal microscopy corroborated a predominant localization at the nuclear pore complexes in these cells. Antibody specificity and reliability of Tpr localization was demonstrated by post-transcriptional tpr gene silencing using siRNAs that eliminated the Tpr signal at the nuclear periphery but did not affect intranuclear staining of Tpr-unrelated proteins. Finally, we defined several sequence and structural features that characterize Tpr polypeptides in different species and used these as a guideline to search whole-genome sequence databases for putative paralogs of Tpr in higher eukaryotes. This approach resulted in identification of the Tpr orthologs in Arabidopsis thaliana and Caenorhabditis elegans, but also in the realization that no further paralogs of Tpr exist in several metazoan model organisms or in humans. In summary, these results reveal Tpr to be a unique protein localized at the nuclear periphery of the somatic cell in mammals.

Place, publisher, year, edition, pages
2002. Vol. 111, no 4, 236-255 p.
National Category
Cell Biology
URN: urn:nbn:se:umu:diva-59012DOI: 10.1007/s00412-002-0208-2ISI: 000179778000003PubMedID: 12424524OAI: diva2:550570
Available from: 2012-09-07 Created: 2012-09-07 Last updated: 2015-12-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Sandblad, Linda
In the same journal
Cell Biology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 36 hits
ReferencesLink to record
Permanent link

Direct link