Type-I insulin-like growth factor receptor gene expression in the chick. Developmental changes and the effect of selection for increased growth on the amount of receptor mRNA

1994 ◽  
Vol 12 (1) ◽  
pp. 3-12 ◽  
Author(s):  
D G Armstrong ◽  
C O Hogg
Keyword(s):  
Rnase Protection Assay ◽  
Reaction Medium ◽  
Type I ◽  
Rnase Protection ◽  
Receptor Mrna ◽  
Type I Igf Receptor ◽  
Mrna Transcripts ◽  
Actin Mrna ◽  
Igf Receptor ◽  
Selection For

ABSTRACT An RNase protection assay is described that allowed the quantitative analysis of chicken type-I IGF receptor mRNA transcripts. The transcripts were measured in extracts of total nucleic acid (TNA) and, under the hybridization conditions described, protected probes of the expected size were obtained. The RNA-RNA hybrids could be quantified in the presence of at least a 1000-fold molar excess of DNA containing sequences which were complimentary to the RNA probe. The amount of protected probe was linearly related to the amount of TNA in the hybridization reaction medium, and this allowed the results to be expressed in the form of mRNA molecules/cell. Type-I IGF receptor mRNA transcripts were detected in all the tissues examined from a 20day-old chick embryo. Their amount ranged from 5 to 24 molecules/cell, in the order liver<breast muscle<leg muscle<heart<brain. The amount of receptor mRNA was 65- to 300-fold less than that of β-actin mRNA. The quantity of type-I IGF receptor mRNA varied significantly throughout embryonic and post-hatch development. Maximum amounts were measured in 21-day-old embryos (a two- to fourfold increase relative to 16-day-old embryos). Thereafter the amount of receptor mRNA decreased, during the 4-week period after hatching, to levels which were significantly lower than that observed in 16-day-old embryos. Throughout the period of embryonic and post-hatch development described here the amount of β-actin mRNA remained constant, indicating that the changes in the quantity of receptor mRNA were due to specific mechanisms acting directly on the steady-state levels of type-I IGF receptor mRNA. Selection for increased growth had no effect on the amount of type-I IGF receptor mRNA. The result was the same when expressed either as molecules/cell or as a percentage of β-actin mRNA.

Glucose regulation of the IGF response system in chondrocytes: induction of an IGF-I-resistant state

1999 ◽  
Vol 276 (4) ◽  
pp. R1164-R1171 ◽  
Author(s):  
K. M. Kelley ◽  
T. R. Johnson ◽  
J. Ilan ◽  
R. W. Moskowitz
Keyword(s):  
Glucose Concentration ◽  
Northern Analysis ◽  
Type I ◽  
Mrna Levels ◽  
Protein Levels ◽  
Receptor Mrna ◽  
Response System ◽  
Type I Igf Receptor ◽  
Igf I ◽  
Igf Receptor

Nonresponsiveness to the growth-stimulatory actions of insulin-like growth factor (IGF)-I in chondrocytes has been reported in a number of disease states associated with impaired glucose metabolism. Primary rabbit chondrocytes were investigated for changes in their IGF response system [type-I IGF receptor and IGF-binding protein (IGFBP) expression] and in their ability to mount a synthetic response to IGF-I [as35S-labeled proteoglycan ([35S]PG) production] in media containing varying ambient glucose concentrations. Whereas basal [35S]PG synthetic rate was unaffected by glucose concentration, synthetic responsiveness to IGF-I was lost in media containing <5 mmol/l glucose or in media containing a “diabetic” glucose concentration (25 mmol/l). IGFBP expression, as measured by Northern analysis of mRNA levels and Western ligand blotting of secreted protein levels, was not significantly altered in the different glucose media, nor were there any differences in the cell surface localization of IGFBPs as assessed by affinity cross-linking with 125I-labeled IGF-I, suggesting that IGFBPs do not induce the IGF-I resistance. The nonresponsiveness to IGF-I in reduced glucose occurred with 25–50% reductions in steady-state levels of IGF type-I receptor mRNA and protein. A significant correlation between IGF receptor mRNA level and synthetic response to IGF-I was observed between 0 and 10 mmol/l glucose concentrations, suggesting that the loss of responsiveness in reduced glucose is manifested at the level of transcription and/or receptor mRNA stability. In contrast, nonresponsiveness to IGF-I in chondrocytes in diabetic glucose concentrations occurred without changes in receptor mRNA and protein levels, suggesting that IGF-I resistance was due to post-ligand-binding receptor defects. It is proposed that IGF-I resistance in chondrocytes subjected to inappropriate glucose levels may constitute an important pathogenic mechanism in degenerative cartilage disorders.

Growth hormone (GH) modulates insulin-like growth factor I (IGF-I) and type I IGF receptor mRNA levels in the ovary of prepubertal GH-deficient rats

1995 ◽  
Vol 132 (4) ◽  
pp. 497-501 ◽  
Author(s):  
Saul Malozowski ◽  
Toni G Parmer ◽  
Sabina Trojan ◽  
George R Merriam ◽  
Geula Gibori ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Type I ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Receptor Mrna ◽  
Type I Igf Receptor ◽  
Igf I ◽  
Igf Receptor

Malozowski S, Parmer TG, Trojan S, Merriam GR, Gibori G, Roberts Jr CT, LeRoith D, Werner H, Zilberstein M. Growth hormone (GH) modulates insulin-like growth factor I (IGF-I) and type I IGF receptor mRNA levels in the ovary of prepubertal GH-deficient rats. Eur J Endocrinol 1995;132:497–501. ISSN 0804–4643 In order to explore the potential role of growth hormone (GH) in modulating insulin-like growth factor I (IGF-I) gene expression in the prepubertal rat ovary, female rats were rendered GH deficient by neonatal administration of monosodium glutamate (MSG). One group of rats received vehicle and served as the control. At 21 days of age, MSG-treated rats received either GH or vehicle for 2 weeks. On days 21, 24, 28 and 31 animals were weighed and subsets were sacrificed for liver RNA extraction. The remaining animals were sacrificed at day 35 when livers and ovaries were collected, and serum was obtained for GH determinations. The IGF-I mRNA levels were estimated by Northern blots and corroborated further by slot-blot analysis. The MSG-treated rats had lower body weights (p < 0.01) and GH levels (p < 0.05) than controls. Growth hormone replacement significantly accelerated the weight gain of MSG-treated rats. At day 24 and thereafter, three RNA IGF-I species (7.5, 1.8 and 0.8–1.2 kB) were seen in the liver. In the ovary, at age 35 days, two major IGF-I mRNA species (7.5 and 0.8–1.2kb) were seen. The MSG treatment consistently reduced the levels of both IGF-I mRNA species in the ovary. Growth hormone administration partially restored their expression, both in the liver and in the ovary. In addition, ovarian type I IGF receptor mRNA levels were increased in the MSG-treated rats when compared to controls. This trend was reversed by GH replacement. In summary, we have found that in prepubertal female rats rendered GH deficient with MSG, ovarian IGF-I gene expression is reduced while type I IGF receptor mRNA levels are increased. These findings are reversed with GH replacement. These results suggest a physiological role for GH in modulating IGF-I and type I IGF receptor genes in the ovary. Saul Malozowski, FDA, HFD-510, Rockville, MD 20897, USA

scholarly journals Cloning and characterization of a naturally occurring soluble form of TGF-β type I receptor

1999 ◽  
Vol 276 (1) ◽  
pp. F88-F95 ◽  
Author(s):  
Mary E. Choi
Keyword(s):  
Transforming Growth Factor ◽  
Rat Kidney ◽  
Rnase Protection Assay ◽  
Neonatal Rat ◽  
Soluble Form ◽  
Type I ◽  
Functional Protein ◽  
Rnase Protection ◽  
Naturally Occurring ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1) has been implicated to play an important role both in the process of normal development and in the pathogenesis of a wide variety of disease processes, including those of the kidney. TGF-β1 regulates diverse cellular functions via a heteromeric signaling complex of two transmembrane serine/threonine kinase receptors (types I and II). Several distinct type I receptors have been described and are thought to determine specificity of the TGF-β response and confer multifunctionality. This report reveals the cloning of a novel, naturally occurring soluble form of TGF-β type I receptor, designated sTβR-I, from a rat kidney cDNA library. In vivo expression of a mRNA transcript encoding the sTβR-I, which lacks the transmembrane and cytoplasmic domains, is confirmed by RT-PCR followed by Southern blot analysis and by RNase protection assay. The sTβR-I mRNA abundance is greater in the neonatal rat kidney compared with the adult rat kidney. Furthermore, sTβR-I is a functional protein capable of binding TGF-β1 ligands in the presence of a TGF-β type II receptor on the cell surface, as determined by affinity cross-linking with 125I-labeled TGF-β1. Studies using p3TP-Lux reporter construct reveal that this novel protein may function as a potentiator of TGF-β signaling. The discovery of a sTβR-I provides an additional level of complexity to the TGF-β receptor system.

Involvement of phenylalanine 23 in the binding of IGF-1 to the insulin and type I IGF receptor

1996 ◽  
Vol 66 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Darren R. Hodgson ◽  
Felicity E.B. May ◽  
Bruce R. Westley
Keyword(s):  
Type I ◽  
Type I Igf Receptor ◽  
Igf Receptor

Melatonin receptor mRNA localization and rhythmicity in the retina of the domestic chick, Gallus domesticus

2002 ◽  
Vol 19 (3) ◽  
pp. 265-274 ◽  
Author(s):  
ARJUN K. NATESAN ◽  
VINCENT M. CASSONE
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Rnase Protection Assay ◽  
Inner Nuclear Layer ◽  
Constant Darkness ◽  
Melatonin Receptor ◽  
Rnase Protection ◽  
Receptor Mrna ◽  
Lower Amplitude

The indoleamine hormone melatonin is synthesized and released by photoreceptors during the night within the chick retina, and confers timing information to modulate retinal physiology. Three subtypes of melatonin receptor with nearly identical pharmacological profiles have been described in chickens and are present in the retina. In this study, the spatial localization and temporal pattern of the mRNA for each of these receptors within the retina are described. The localization and rhythmicity of receptor mRNA were analyzed using in situ hybridization and RNase protection assay, respectively, with probes against specific nucleotide sequences encoding these receptors. Mel1A and Mel1C receptor mRNA have similar patterns of expression, primarily in the inner segments of photoreceptors, vitread portion of the inner nuclear layer, and in the retinal ganglion cell layer. Mel1B receptor mRNA is expressed at higher levels in the retina, with expression in photoreceptors, throughout the inner nuclear layer, and in the ganglion cell layer. Mel1A receptor mRNA is rhythmic in both light:dark (LD) cycles and in constant darkness (DD); Mel1A peaks during midday and mid-subjective day, respectively. Mel1C receptor mRNA is also rhythmically expressed in LD, but with a lower amplitude, such that transcript is high during the day and low during the night. In DD, Mel1C rhythms become 180 deg out of phase with a slight increase at night. Mel1B mRNA expression was highly variable and arrhythmic.

Detection and downregulation of type I IGF receptor expression by antibody-conjugated quantum dots in breast cancer cells

2008 ◽  
Vol 114 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Hua Zhang ◽  
Deepali Sachdev ◽  
Chun Wang ◽  
Allison Hubel ◽  
Martine Gaillard-Kelly ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Quantum Dots ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Receptor Expression ◽  
Type I ◽  
Type I Igf Receptor ◽  
Igf Receptor

Immunoreactive and receptor-active insulin-like growth factor-I (IGF-I) and IGF-binding protein in blood plasma from the freshwater fish Macquaria ambigua (golden perch)

1993 ◽  
Vol 136 (2) ◽  
pp. 191-198 ◽  
Author(s):  
T. A. Anderson ◽  
L. R. Bennett ◽  
M. A. Conlon ◽  
P. C. Owens
Keyword(s):  
Binding Protein ◽  
Size Exclusion ◽  
Type I ◽  
Factor I ◽  
Type I Igf Receptor ◽  
Receptor Assay ◽  
Igf I ◽  
Igf Binding ◽  
Igf Receptor ◽  
Igf Binding Protein

ABSTRACT The presence of insulin-like growth factor-I (IGF-I)-related molecules and IGF-binding factors in blood from golden perch, Macquaria ambigua, an Australian native freshwater fish, was investigated. Serum was acidified to dissociate IGF and IGF-binding protein complexes that might be present, and fractionated by size-exclusion high-performance liquid chromatography at pH 2·8. Fractions were neutralized and their activities assessed by (i) an immunoassay for mammalian IGF-I which also detects chicken IGF-I but in which all known forms of IGF-II react very poorly, (ii) a receptor assay for IGF-II in which all known forms of IGF-I react poorly, and (iii) a type-I IGF receptor assay in which mammalian IGF-I and IGF-II polypeptides are almost equivalent. No IGF-II-like activity was detected. Three peaks of IGF-I-like activity were detected by IGF-I immunoassay and type-I IGF receptor assay. The major peak of activity was similar in molecular size to human IGF-binding protein-3, 45–55 kDa ('large IGF'), and a minor peak of activity which was similar in size to mammalian IGFs, 7·5 kDa. A third peak of activity was observed eluting at a time which indicates that it is a smaller molecule than any previously described IGF. The large IGF was temperature-sensitive, but was not a binding protein for 125I-labelled human IGF-I (hIGF-I). This material therefore was able to bind to anti-hIGF-I antibodies and to human type-I IGF receptors, and may represent the fish equivalent of mammalian prepro-IGFs. The two smallest forms of IGF activity identified by IGF-I radioimmunoassay and type-I radioreceptor assay following acidic size-exclusion chromatography were able to stimulate protein synthesis by L-6 myoblasts in culture, although large IGF did not. When fresh (but not frozen and thawed) golden perch serum was incubated with 125I-labelled hIGF-I and then fractionated by size-exclusion liquid chromatography at pH 7·4 through Sephadex G-100, the radioactivity became associated with a complex, intermediate in size between free IGF-I and the major IGF-binding protein in human serum. The association of 125I-labelled hIGF-I with the complex was inhibited by the presence of unlabelled hIGF-I in the incubation. These studies show that receptor-active, immunoreactive and bioactive IGF-I-like activity is present in golden perch serum, and demonstrate the presence of an IGF-I-binding factor in this species. Journal of Endocrinology (1993) 136, 191–198

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