Targeted inactivation of the insulin receptor gene in mouse 3T3-L1 fibroblasts via homologous recombination.

Accili, Domenico; Taylor, Simeon I.

doi:10.1073/pnas.88.11.4708

Cited by 87 publications

(44 citation statements)

References 35 publications

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“…High concentrations of insulin (1 M) are thought to induce differentiation of 3T3-L1 preadipocytes through activation of the IGF I receptor (36). However, gene targeting of one insulin receptor allele in 3T3-L1 preadipocytes impaired the ability of these cells to differentiate into adipocytes (37), suggesting that insulin can play a direct role in the differentiation of the 3T3-L1 cells. The present studies support the notion that the insulin receptor cytoplasmic domain is also capable of initiating the intracellular signals sufficient for adipocyte differentiation.…”

Section: Resultsmentioning

confidence: 99%

CSF-1 Receptor/Insulin Receptor Chimera Permits CSF-1-dependent Differentiation of 3T3-L1 Preadipocytes

Chaika¹,

Chaika²,

Volle³

et al. 1997

Journal of Biological Chemistry

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A chimeric growth factor receptor (CSF1R/IR) was constructed by splicing cDNA sequences encoding the extracellular ligand binding domain of the human colony stimulating factor-1 (CSF-1) receptor to sequences encoding the transmembrane and cytoplasmic domains of the human insulin receptor. The addition of CSF-1 to cells transfected with the CSF1R/IR chimera cDNA stimulated the tyrosine phosphorylation of a protein that was immunoprecipitated by an antibody directed against the carboxyl terminus of the insulin receptor. Phosphopeptide maps of the 32 P-labeled CSF1R/IR protein revealed the same pattern of phosphorylation observed in 32 P-labeled insulin receptor ␤ subunits. CSF-1 stimulated the tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and Shc in cells expressing the CSF1R/IR chimera. Lipid accumulation and the expression of a differentiation-specific marker demonstrated that 3T3-L1 preadipocytes undergo CSF-1-dependent differentiation when transfected with the CSF1R/IR chimera cDNA but not when transfected with the expression vector alone. A 12-amino acid deletion within the juxtamembrane region of the CSF1R/IR (CSF1R/IR⌬960) blocked CSF-1-stimulated phosphorylation of IRS-1 and Shc but did not inhibit CSF-1-mediated differentiation of 3T3-L1 preadipocytes. These observations indicate that adipocyte differentiation can be initiated by intracellular pathways that do not require tyrosine phosphorylation of IRS-1 or Shc.A primary goal in the study of insulin action is the identification of the intracellular pathways that lead ultimately to changes in the rates of growth, development, and metabolism in primary target tissues of insulin (e.g. adipose, muscle, and liver). One strategy for the study of insulin-sensitive intracellular signaling has been to identify structural features within the insulin receptor that are important components of divergent signal transduction pathways. The goal of this strategy has been to create mutations within specific receptor sequences that result in the selective disruption of some insulin-regulated metabolic pathways while leaving others intact. Deletion mutagenesis of the insulin receptor cytoplasmic domain has generated insulin receptors with altered biological properties (1-4). Experiments with these receptor mutants have led to the suggestion that different regions of the insulin receptor cytoplasmic domain may play roles in modulating the distinct biological effects of insulin. Most mutations of the insulin receptor cytoplasmic domain have removed or altered autophosphorylation sites within the cytoplasmic domain (5-8). This approach has furthered the notion that tyrosine phosphorylation and the tyrosine kinase encoded within the receptor ␤ subunit are essential components of normal insulin action. The majority of structure/function analyses of the insulin receptor, however, have been performed in cells expressing low levels of endogenous insulin receptors, e.g. Chinese hamster ovary (CHO) 1 or Rat-1 fibroblasts cell lines (reviewed in Ref. 9). Although su...

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Section: Resultsmentioning

confidence: 99%

CSF-1 Receptor/Insulin Receptor Chimera Permits CSF-1-dependent Differentiation of 3T3-L1 Preadipocytes

Chaika¹,

Chaika²,

Volle³

et al. 1997

Journal of Biological Chemistry

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“…In this respect it is interesting to note that IGF-1 can exert hypoglycaemic, but not lipogenic effects, in IR ±/± mice [27]. In a different model, we have previously shown that partial inactivation of the IR gene in 3T3-L1 cells is associated with impaired adipocyte differentiation, and that this defect can be reversed by over-expression of IRs [28]. Interestingly, not all dermal areas are equally susceptible to insulin resistance; for example, the decrease of fat content in abdominal and thoracic areas is more marked than in dorsal areas.…”

Section: Discussionmentioning

confidence: 99%

Lack of insulin receptors affects the formation of white adipose tissue in mice. A morphometric and ultrastructural analysis

et al. 1998

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Insulin receptors (IRs) mediate insulin action upon target cells [1]. Disorders of IR function are a well established, albeit rare, cause of insulin resistance and diabetes mellitus [2±4]. In mice, targeted ablation of IR expression results in lethal diabetic ketoacidosis [5±7]. Unlike children with homozygous nonsense mutations of the IR gene, IR ±/± mice do not develop substantial growth retardation, fasting hypoglycaemia, or signs of hyperandrogenism.The lack of gross growth retardation in IR ±/± mice is an unexpected finding. To understand better the causes of this apparent discrepancy between the human paradigm and the mouse model, we have recently performed genetic crosses of IR ±/± mice with mice lacking insulin-like growth factor-1 (IGF-1) receptors (IGF-1Rs) and . The results of these experiments indicate that IRs do indeed affect embryonic growth. The growth-promoting actions of IRs occur in response to IGF-2, rather than insulin, binding. The interaction between IRs and IGF-2 plays an important role during the last phase of mouse gestation. Based on these data, we have suggested that the lack of a growth-retarded phenotype in IR ±/± mice may be due to the shorter duration of mouse gestation Diabetologia (1998) 41: 171±177

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“…Therefore, it can be speculated that FoxOs may have some important roles in these tissues. Insulin or other growth factors are important for adipocyte differentiation [89][90][91][92]. However, it has not been known about the mechanism how these growth factors can regulate adipocyte differentiation.…”

Section: Adipose Tissuesmentioning

confidence: 99%

The FoxO transcription factors and metabolic regulation

2007

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Forkhead transcription factors FoxOs are conserved beyond species and regulated by insulin signaling pathway. FoxOs have diverse functions on differentiation, proliferation and cell survival. In calorie restriction (CR) or starvation, FoxOs are in nucleus, active transcriptionally, and increase hepatic glucose production, decrease insulin secretion, increase food intake and cause degradation of skeletal muscle for supplying substrates for glucose production. However, even in insulin resistance due to excessive calorie intake, FoxOs are active and causes type 2 diabetes and hyperlipidemia. The understanding of molecular mechanism how FoxOs affect glucose or lipid metabolism will shed light on the novel therapy of type 2 diabetes and the metabolic syndrome.

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Targeted inactivation of the insulin receptor gene in mouse 3T3-L1 fibroblasts via homologous recombination.

Cited by 87 publications

References 35 publications

CSF-1 Receptor/Insulin Receptor Chimera Permits CSF-1-dependent Differentiation of 3T3-L1 Preadipocytes

CSF-1 Receptor/Insulin Receptor Chimera Permits CSF-1-dependent Differentiation of 3T3-L1 Preadipocytes

Lack of insulin receptors affects the formation of white adipose tissue in mice. A morphometric and ultrastructural analysis

The FoxO transcription factors and metabolic regulation

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