Biomaterial Database

Multiple Ras signals pattern the Drosophila ovarian follicle cells. 1997

T Lee, and D J Montell

Department of Biological Chemistry, Johns Hopkins School of Medicine, Baltimore, Maryland 21205-2185, USA.

During Drosophila oogenesis, spatially restricted activity of the TORPEDO receptor tyrosine kinase first recruits follicle cells adjacent to the oocyte to a posterior cell fate and then specifies dorsal follicle cells. Another receptor tyrosine kinase, BREATHLESS, stimulates migration of the anterior follicle cells known as border cells. Since Ras is known to mediate many receptor tyrosine kinase effects, we have investigated the role of Ras in follicle cell fate determination, differentiation, and migration throughout oogenesis. Early ectopic Ras activity induced transient expression of posterior follicle cell markers in anterior follicle cells, but did not inhibit anterior differentiation. Later ectopic Ras activity inhibited anterior follicle cell differentiation but did not induce posterior marker expression. Complete transformation of anterior follicle cells to posterior follicle cells required early ectopic Ras activity in egg chambers where terminal differentiation of anterior cells was inhibited. These results suggest that, in vivo as in vitro, Ras can have diverse effects on different cells, but, in addition, Ras activity can have different effects on the same cells at different stages in their development.

UI	MeSH Term	Description	Entries
D009687	Nuclear Proteins	Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.	Nucleolar Protein,Nucleolar Proteins,Nuclear Protein,Protein, Nuclear,Protein, Nucleolar,Proteins, Nuclear,Proteins, Nucleolar
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D004330	Drosophila	A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.	Fruit Fly, Drosophila,Drosophila Fruit Flies,Drosophila Fruit Fly,Drosophilas,Flies, Drosophila Fruit,Fly, Drosophila Fruit,Fruit Flies, Drosophila
D004627	Embryonic Induction	The complex processes of initiating CELL DIFFERENTIATION in the embryo. The precise regulation by cell interactions leads to diversity of cell types and specific pattern of organization (EMBRYOGENESIS).	Embryonic Inductions,Induction, Embryonic,Inductions, Embryonic
D005260	Female		Females
D006080	Ovarian Follicle	An OOCYTE-containing structure in the cortex of the OVARY. The oocyte is enclosed by a layer of GRANULOSA CELLS providing a nourishing microenvironment (FOLLICULAR FLUID). The number and size of follicles vary depending on the age and reproductive state of the female. The growing follicles are divided into five stages: primary, secondary, tertiary, Graafian, and atretic. Follicular growth and steroidogenesis depend on the presence of GONADOTROPINS.	Graafian Follicle,Atretic Follicle,Ovarian Follicles,Atretic Follicles,Follicle, Atretic,Follicle, Graafian,Follicle, Ovarian,Follicles, Atretic,Follicles, Graafian,Follicles, Ovarian,Graafian Follicles
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D018631	ras Proteins	Small, monomeric GTP-binding proteins encoded by ras genes (GENES, RAS). The protooncogene-derived protein, PROTO-ONCOGENE PROTEIN P21(RAS), plays a role in normal cellular growth, differentiation and development. The oncogene-derived protein ONCOGENE PROTEIN P21(RAS) can play a role in aberrant cellular regulation during neoplastic cell transformation (CELL TRANSFORMATION, NEOPLASTIC). This enzyme was formerly listed as EC 3.6.1.47.	Gene Products, ras,ras GTPase,ras Protein,ras GTPases,GTPase, ras,GTPases, ras,Protein, ras,ras Gene Products
D019070	Cell Lineage	The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.	Cell Lineages,Lineage, Cell,Lineages, Cell