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Nucleolar localization of an isoform of the IGF-I precursor
Background
Alternative exons encode different isoforms of the human insulin-like growth factor-I (IGF-I) precursor without altering mature IGF-I. We hypothesized that the various IGF-I precursors may traffic IGF-I differently. Chimeric IGF-I precursors were made with green fluorescent protein (GFP) cloned between the signal and mature IGF-I domains.
Results
Chimeras containing exons 1 or 2 were located in the cytoplasm, consistent with a secretory pathway, and suggesting that both exons encoded functional signal peptides. Exon 5-containing chimeras localized to the nucleus and strongly to the nucleolus, while chimeras containing exon 6 or the upstream portion of exon 5 did not. Nuclear and nucleolar localization also occurred when the mature IGF-I domain was deleted from the chimeras, or when signal peptides were deleted.
Conclusions
We have identified a nucleolar localization for an isoform of the human IGF-I precursor. The findings are consistent with the presence of a nuclear and nucleolar localization signal situated in the C-terminal part of the exon 5-encoded domain with similarities to signals in several other growth factors.
Complete Metadata
| @type | dcat:Dataset |
|---|---|
| accessLevel | public |
| bureauCode |
[
"009:25"
]
|
| contactPoint |
{
"fn": "NIH",
"@type": "vcard:Contact",
"hasEmail": "mailto:info@nih.gov"
}
|
| description | Background Alternative exons encode different isoforms of the human insulin-like growth factor-I (IGF-I) precursor without altering mature IGF-I. We hypothesized that the various IGF-I precursors may traffic IGF-I differently. Chimeric IGF-I precursors were made with green fluorescent protein (GFP) cloned between the signal and mature IGF-I domains. Results Chimeras containing exons 1 or 2 were located in the cytoplasm, consistent with a secretory pathway, and suggesting that both exons encoded functional signal peptides. Exon 5-containing chimeras localized to the nucleus and strongly to the nucleolus, while chimeras containing exon 6 or the upstream portion of exon 5 did not. Nuclear and nucleolar localization also occurred when the mature IGF-I domain was deleted from the chimeras, or when signal peptides were deleted. Conclusions We have identified a nucleolar localization for an isoform of the human IGF-I precursor. The findings are consistent with the presence of a nuclear and nucleolar localization signal situated in the C-terminal part of the exon 5-encoded domain with similarities to signals in several other growth factors. |
| distribution |
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"@type": "dcat:Distribution",
"title": "Official Government Data Source",
"mediaType": "text/html",
"description": "Visit the original government dataset for complete information, documentation, and data access.",
"downloadURL": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117215/"
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|
| identifier | https://healthdata.gov/api/views/2swy-djma |
| issued | 2025-07-14 |
| keyword |
[
"growth-factors",
"igf-i",
"nih",
"nucleolar-localization",
"protein-isoforms"
]
|
| landingPage | https://healthdata.gov/d/2swy-djma |
| modified | 2025-09-06 |
| programCode |
[
"009:033"
]
|
| publisher |
{
"name": "National Institutes of Health",
"@type": "org:Organization"
}
|
| theme |
[
"NIH"
]
|
| title | Nucleolar localization of an isoform of the IGF-I precursor |
