References

Notes: A continuous cell line of highly contact-inhibited cells (NIH/3T3) has been developed from NIH Swiss mouse embryo cultures.Its growth properties are similar to those of 3T3 and BALB/3T3.Although 3T3 is relatively insenitive to focus formation by murine sarcoma viruses, cloned lines of both NIH/3T3 ond BALB/3T3 have been isolated that are highly sensitive to sarcoma virus focus formation and leukemoa virus growth. The sesitivity and specificity are comparable to those foune with promary embryo cells. MSV-transformed lines of NIH/3T3 have been obtained.
Reference ID: 1300

Notes: We describe a cell-lineage marking system applicable to the vertebrate nervous system. The basis of the technique is gene transfer using the retroviral vector system. We used Escherichia coli bet-galactosidase as a marker gene and demonstrate a high level of expression of this marker from the viral long terminal repeat promoter, with simultaneous expression of the Tn5 neo gene from the simian virus 40 early promoter. This expression has allowed us to detect individual infected cells histochemically. We applied this marking technique to the study of lineage relationships in the developing vertebrate nervous system, both in vivo and histochemically identified clones of marked neural cells. In addition, wej used ttis virkus to infect cultures of rat cerebral cortex and have analyzed the clonal relationships of morphologicall different neural cell types.
Reference ID: 1506

Notes: Science Weinberg and his associates succeeded in isolating a v-ras-related human oncogene(7),NIH3T3 cells have been used for isolation and assay of transforming genes (3).Recently, we found that the so-called NIH3T3 cells distributed in the world are not one cell strain of the same origin.
Reference ID: 1301

Reference ID: 60

Notes: G-protein coupled receptors for the pineal hormone melatonin have been partially cloned from rats. However, insufficient information about their cDNA sequences has hindered studies of their distribution and physiological responses to melatonin using rats as an animal model. We have cloned cDNAs of two rat membrane melatonin receptor subtyppes, melatonin receptor 1a(MT1) and melatonin receptor 1b(MT2), using a rapid amplification of cDNA end (RACE) method. The rat MT1 and MT1 cDNAs encode proteins of 353 and 364 amino acids, respectively, and show 78-93% identities with the human and mouse counterparts. Stable expression of either rat MT1 or MT2 in NIH3T3 cells resulted in high affinity 2-[125I]-iodomelatonin binding (Kd=73.2 +- 9.0 ...) and exhibited a similar rank order of inhibition of specific 125I-Mel binding by five ligands (2-idodomelatonin > melatonin > 6-hydroxymelatonin > luzindole > N-acetyl-6-hydroxytryptamine). RT-PCR analysis showed that MT1 is highly expressed in the hypothalamus, lung, kidney, adrenal ggland, stomach, and ovary, while MT2 is highly expressed in the hypothalamus, ling, kidney, adrenal gland, stomach, and ovary, while MT2 is highly expressed in the hippocampus, kidney, and ovary. We also performed multi-cell RT-PCR to examine the expression of mRNAs encoding MT1 and MT2 in adult GnRH neurons. MT1 was weakly expressed in male GnRH neurons and was less expressed in the female neurons. MT2 expression was undetectable in GnRH neurons from either sex. This study delineates the gene structures, fundamental properties, and may offer opportunities to assess the physiological significance of melatoni in rats.
Reference ID: 6412

Notes: Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London SW3 6JB, UKFAU - Tzircotis, George
Abstract: The accumulation of the extracellular matrix glycosaminoglycan hyaluronan by tumours and tumour-associated stroma promotes cancer cell invasion and metastasis. Using the Dunn chamber chemotaxis assay, we demonstrate for the first time that high molecular mass hyaluronan acts as a soluble chemoattractant promoting the directional migration of MDA-MB-468 and MDA-MB-231 breast cancer cells. Moreover, chemotaxis towards hyaluronan, but not foetal bovine serum, can be abrogated following treatment of the cells with siRNA oligonucleotides to downregulate CD44 expression. These data indicate that CD44 is the principal receptor mediating this response and that CD44 expression is not a general requirement for cell migration and gradient sensing, rather it elicits a ligand-specific response. However, expression of CD44 alone is not sufficient to drive chemotaxis towards hyaluronan, as NIH-3T3 fibroblasts were unable to respond to a hyaluronan gradient even when transfected with high levels of human CD44. For NIH-3T3 cells to bind exogenous hyaluronan, it was necessary to both increase the level of receptor expression and remove a hyaluronan pericellular matrix. Together, these studies reveal a direct mechanism for promoting cell invasion into the hyaluronan-rich matrix and predict that in the complex multicellular environment in vivo, multiple mechanisms exist to regulate the ability of a cell to respond to a chemotactic hyaluronan gradient
Reference ID: 6413