Ectopic proteins

A second characteristic of cancer cells is that they usually appear less differentiated than the tissues from which they arise and are more like embryonic cells. Many cancers produce ectopic proteins, proteins inappropriate to the tissue involved and often identical to proteins synthesized by embryonic or fetal cells. A well-known example is a-fetoprotein, a 72-kDa glycoprotein normally present in serum in almost undetectable amounts but present in large amounts when some types of cancer are present/ A third property of cancers is the tendency toward metastasis, the detachment of cells from the cancer and their development in distant parts of the body. -1... 

E (entgegen) configuration 43 E3 binding protein 796 Eadie-Hofctee plot 460 E-cadhedrin 574 Echinodermata 25 Ectoderm 23 Ectoenzymes 409 Ectopic proteins 573 Edelman, Gerald M. 84 Edman degradation 118 EDTA. See Ethylenediaminetetraacetic acid Effector(s) of allosteric enzymes 473-475 EF-hand motif 313, 317 EGF (epithelial growth factor), definition of 577... 

Recombinant plasmids specific for bacteria, yeast, and even mammalian cells have been generated in the laboratory and exploited for a variety of basic and applied research applications. Specifically, recombinant expression plasmids can be constructed in order to express the ectopic protein encoded by the foreign (trans) gene in the appropriate host cell. Recombinant plasmids of mammalian cells are based on viruses, rather than on episomal DNA. Only the DNA replication function of the virus is incorporated into the plasmid, so that the plasmid is replicated without producing the active virus. In the ease of human cells, simian virus 40 (SV40) is commonly used to generate recombinant DNA. 

Lucas, P. A., Laurencin, C., Syftestad, G. T., Domb, A., Goldberg, V. M., Caplan, A. I., and Langer, R., Ectopic induction of cartilage and bone by water-soluble proteins from bovine bone using a polyanhydride delivery vehicle, J. Control. Rel. In Press. 

Bone morphogenetic proteins (BMPs) A family (eight or more) of secreted proteins with a variety of actions on bone many induce ectopic bone growth. 

Hinds, P. H., Mittnacht, S., Dulic, V., Arnold, A., Reed, S. I., and Weilberg, R. A. (1992). Regulation of the retinoblastoma protein functions by ectopic expression of human cyclins. Cell 70 993-1006. 

The most dramatic illustration of the evolutionary conservation of homeobox genes comes from experiments that swap Drosophila and mammalian cognates and test for functional equivalence. McGinnis and co-workers have reported remarkable phenotypic similarities in flies that misexpress Drosophila homeobox genes or their mammalian counterparts. Indeed, this ectopic expression assay in Drosophila indicates that the Drosophila and cognate mammalian homeobox proteins are essentially functionally identical. 

How might cellular growth drive Gl/S transitions A mechanism in which an unstable, translationally regulated protein limits Gl/S transitions provides one possible explanation. Consistent with this, we found that ectopic Rasvl2 or d-Myc increased levels of cyclin E, and that this effect was post-transcriptional (Prober ... 

SABLOWSKI, R.W.M., BAULCOME, D.C, BEVAN, M., Expression of a flower-specific Myb protein in leaf cells using a viral vector causes ectopic activation of a target promoter, Proc Natl Acad Sci USA, 1996,92, 6901-6905. 

Sakamoto, A., Chen, M., Kobayashi, T., Kronenberg, H. M., and Weinstein, L. S. (2005) Chondrocyte-specific knockout of the G protein G(s)alpha leads to epiphyseal and growth plate abnormalities and ectopic chondrocyte formation. J. Bone Miner. Res. 20, 663-671. 

Two reasons could explain the failure of soluble SI SCF to induce long term growth of hematopoietic cells on stroma. One might be the production of inadequate levels of protein by SI stroma and by SESl and MMCE cells ectopically expressing SI SCF. The other could be an antagonistic function of the mutated SI SCF compared to the membrane-bound isoform. To test for these possibilities we added recombinant soluble SCF, that is produced as a cleavage product of mb SCF, to TEl feeder cocultures. 

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