Regulation of an H-ras-related transcript by parathyroid hormone in rat osteosarcoma cells.
Mol Endocrinol
; 6(9): 1425-32, 1992 Sep.
Article
in En
| MEDLINE
| ID: mdl-1359401
ABSTRACT
The rat osteosarcoma cell line UMR 106-01 is a commonly used model system for the study of osteoblast function. However, it also expresses a phenotype characteristic of transformed cells. To test whether the latter could be accounted for by aberrant oncogene expression, we probed Northern blots of UMR and other osteoblastic cells with a panel of oncogene probes. These blots, when probed with a cDNA specific for v-H-ras, revealed a 7.0-kilobase (kb) H-ras-related transcript (designated HRRT) in UMR 106-01 cells that was not expressed in other osteoblastic cells. Osteoblast-enriched calvarial cells expressed the typical 1.1-kb H-ras mRNA, which was absent in UMR cells. Additionally, Western blots of lysates of UMR cells documented the presence of three proteins immunologically related to H-rasp21. To determine whether HRRT represented a recombinant retrovirus product, Northern blots were probed with a cDNA specific for the highly conserved gag-pol region of Moloney murine leukemia virus. These blots showed parallel cross-reactivity with an apparently identical transcript of 7.0 kb. The 7.0-kb transcripts detected by both v-H-ras and gag-pol probes declined to the same extent after treatment with concentrations of PTH known to inhibit proliferation of these cells. PTH regulated the abundance of HRRT in a time- and dose-dependent manner, with greatest repression of the transcript after 8 h of treatment with 10(-8) M PTH. The decrease in HRRT could not be completely accounted for by changes in transcriptional activity, as determined by nuclear run-on assays.(ABSTRACT TRUNCATED AT 250 WORDS)
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Osteoblasts
/
Parathyroid Hormone
/
Retroviridae
/
Bone Neoplasms
/
Osteosarcoma
/
Gene Expression Regulation, Neoplastic
/
Oncogene Protein p21(ras)
/
Cell Transformation, Neoplastic
/
Genes, ras
/
Proviruses
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Mol Endocrinol
Journal subject:
BIOLOGIA MOLECULAR
/
ENDOCRINOLOGIA
Year:
1992
Document type:
Article