Morphogenesis (from the Greek morphê shape and genesis creation, literally, "beginning of the shape"), is the biological process that causes an organism to develop its shape. It is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation.
The process controls the organized spatial distribution of cells during the embryonic development of an organism. Morphogenesis can take place also in a mature organism, in cell culture or inside tumor cell masses. Morphogenesis also describes the development of unicellular life forms that do not have an embryonic stage in their life cycle, or describes the evolution of a body structure within a taxonomic group.
Morphogenetic responses may be induced in organisms by hormones, by environmental chemicals ranging from substances produced by other organisms to toxic chemicals or radionuclides released as pollutants, and other plants, or by mechanical stresses induced by spatial patterning of the cells.
Some of the earliest ideas on how physical and mathematical processes and constraints affect biological growth were written by D'Arcy Wentworth Thompson and Alan Turing. These works postulated the presence of chemical signals and physico-chemical processes such as diffusion, activation, and deactivation in cellular and organismic growth. The fuller understanding of the mechanisms involved in actual organisms required the discovery of DNA and the development of molecular biology and biochemistry. The term Histomorphogenesis was coined by Ricqlès et al. (2001) for the same process in the bone histology.
Several types of molecules are particularly important during morphogenesis. Morphogens are soluble molecules that can diffuse and carry signals that control cell differentiation decisions in a concentration-dependent fashion. Morphogens typically act through binding to specific protein receptors. An important class of molecules involved in morphogenesis are transcription factor proteins that determine the fate of cells by interacting with DNA. These can be coded for by master regulatory genes and either activate or deactivate the transcription of other genes; in turn, these secondary gene products can regulate the expression of still other genes in a regulatory cascade. Another class of molecules involved in morphogenesis are molecules that control cell adhesion. For example, during gastrulation, clumps of stem cells switch off their cell-to-cell adhesion, become migratory, and take up new positions within an embryo where they again activate specific cell adhesion proteins and form new tissues and organs. Several examples that illustrate the roles of morphogens, transcription factors and cell adhesion molecules in morphogenesis are discussed below.
Morphogenesis arises because of changes in the cellular structure or how cells interact in tissues. Certain cell types "sort out". Cell "sorting out" means that when the cells physically interact they move so as to sort into clusters that maximize contact between cells of the same type. The ability of cells to do this comes from differential cell adhesion. Two well-studied types of cells that sort out are epithelial cells and mesenchymal cells. During embryonic development there are some cellular differentiation events during which mesenchymal cells become epithelial cells and at other times epithelial cells differentiate into mesenchymal cells (see Epithelial-mesenchymal transition). Following epithelial-mesenchymal transition, cells can migrate away from an epithelium and then associate with other similar cells in a new location.
During embryonic development, cells are restricted to different layers due to differential affinities. One of the ways this can occur is when cells share the same cell-to-cell adhesion molecules. For instance, homotypic cell adhesion can maintain boundaries between groups of cells that have different adhesion molecules. Furthermore, cells can sort based upon differences in adhesion between the cells, so even two populations of cells with different levels of the same adhesion molecule can sort out. In cell culture cells that have the strongest adhesion move to the center of a mixed aggregates of cells.
The molecules responsible for adhesion are called cell adhesion molecules (CAMs). Several types of cell adhesion molecules are known and one major class of these molecules are cadherins. There are dozens of different cadherins that are expressed on different cell types. Cadherins bind to other cadherins in a like-to-like manner: E-cadherin (found on many epithelial cells) binds preferentially to other E-cadherin molecules. Mesenchymal cells usually express other cadherin types such as N-cadherin.
The extracellular matrix (ECM) is involved with separating tissues, providing structural support or providing a structure for cells to migrate on. Collagen, laminin, and fibronectin are major ECM molecules that are secreted and assembled into sheets, fibers, and gels. Multisubunit transmembrane receptors called integrins are used to bind to the ECM. Integrins bind extracellularly to fibronectin, laminin, or other ECM components, and intracellularly to microfilament-binding proteins α-actinin and talin to link the cytoskeleton with the outside. Integrins also serve as receptors to trigger signal transduction cascades when binding to the ECM. A well-studied example of morphogenesis that involves ECM is mammary gland ductal branching.
- Pattern formation
- French flag model
- Axon guidance
- Eye development
- Polycystic kidney disease 2
- Drosophila embryogenesis
- ^ Gilbert, Scott F. (2000). "Morphogenesis and Cell Adhesion". Developmental biology (6th ed.). Sunderland, Mass: Sinauer Associates. ISBN 0-87893-243-7. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=morphogenesis&rid=dbio.section.372.
- ^ Fata JE, Werb Z, Bissell MJ (2004). "Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes". Breast Cancer Res. 6 (1): 1–11. doi:10.1186/bcr634. PMC 314442. PMID 14680479. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=314442.
- ^ Sternlicht MD (2006). "Key stages in mammary gland development: the cues that regulate ductal branching morphogenesis". Breast Cancer Res. 8 (1): 201. doi:10.1186/bcr1368. PMC 1413974. PMID 16524451. http://breast-cancer-research.com/content/8/1/201.
- Ricqles, A. DE; Mateus, O.; Antunes, M. Telles ; & Taquet, P. (2001). Histomorphogenesis of embryos of Upper Jurassic Theropods from Lourinhã (Portugal). Comptes rendus de l'Académie des sciences - Série IIa - Sciences de la Terre et des planètes. 332(10): 647-656.
- Artificial Life model of multicellular morphogenesis with autonomously generated gradients for positional information
The development of phenotype Key concepts Genetic architecture Non-genetic influences Developmental architecture Evolution of genetic systems Influential figures Debates
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morphogenesis — mor pho*gen e*sis (Biol.) The development of the tissues and organs of an organism; the formation of structural features of an organism. [PJC] … The Collaborative International Dictionary of English
morphogenesis — morphogenesis. См. морфогенез. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
morphogenesis — (n.) 1863 in biology; 1958 in geology; from MORPHO (Cf. morpho ) + GENESIS (Cf. genesis). Related: Morphogenetic … Etymology dictionary
morphogenesis — [môr΄fō jen′ə sis] n. [ModL: see MORPH & GENESIS] Zool. the structural changes occurring during the development of an organism, organ, or part morphogenetic [môr΄fōjə net′ik] adj … English World dictionary
MOrphogenesis — Infobox Album Name = MOrphogenesis Type = ep Artist = ...And Oceans Released = 2000 Recorded = Genre = Melodic black metal, heavy metal, industrial metal, avant garde metal Length = Label = Producer = Reviews = Last album = ...And Oceans (Box… … Wikipedia
morphogenesis — morphogenetic /mawr foh jeuh net ik/, morphogenic, adj. /mawr feuh jen euh sis/, n. Embryol. the development of structural features of an organism or part. [1880 85; MORPHO + GENESIS] * * * ▪ biological process the shaping of an organism by … Universalium
Morphogenesis — organo atsiradimas bei formavimasis statusas T sritis gyvūnų raida, augimas, ontogenezė, embriologija atitikmenys: lot. Morphogenesis ryšiai: platesnis terminas – pagrindiniai terminai siauresnis terminas – ląstelių atsiradimas ir formavimasis… … Veterinarinės anatomijos, histologijos ir embriologijos terminai
Morphogenesis — organo atsiradimas bei formavimasis statusas T sritis gyvūnų raida, augimas, ontogenezė, embriologija atitikmenys: lot. Morphogenesis ryšiai: platesnis terminas – ikiembrioninis laikotarpis siauresnis terminas – embrioninis diskas siauresnis… … Veterinarinės anatomijos, histologijos ir embriologijos terminai
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Morphogenesis — organo atsiradimas ir formavimasis statusas T sritis embriologija atitikmenys: lot. Morphogenesis ryšiai: platesnis terminas – dauginimasis siauresnis terminas – gastrulės susidarymas siauresnis terminas – nervinio vamzdžio formavimasis sinonimas … Medicininės histologijos ir embriologijos vardynas