Gastrulation
| Gastrulation | |
|---|---|
blastula, made up of one layer, folds inward and enlarges to create a gastrula. This diagram is color-coded: ectoderm, blue; endoderm, green; blastocoel (the yolk sac), yellow; and archenteron (the primary gut), purple. | |
| Identifiers | |
| MeSH | D054262 |
| Anatomical terminology] | |
Gastrulation is the stage in the early
Gastrula layers
In
Gastrulation takes place after
and organs in the developing embryo.- The ectoderm gives rise to epidermis, the nervous system, and to the neural crest in vertebrates.[2]
- The endoderm gives rise to the epithelium of the digestive system and respiratory system, and organs associated with the digestive system, such as the liver and pancreas.[2]
- The
Following gastrulation, cells in the body are either organized into sheets of connected cells (as in
Basic cell movements
Although gastrulation patterns exhibit enormous variation throughout the animal kingdom, they are unified by the five basic types of cell movements that occur during gastrulation:[2][9]
- Invagination
- Involution
- Ingression
- Delamination
- Epiboly
Etymology
The terms "gastrula" and "gastrulation" were coined by Ernst Haeckel, in his 1872 work "Biology of Calcareous Sponges".[10] Gastrula (literally, "little belly") is a neo-Latin diminutive based on the Ancient Greek γαστήρ gastḗr ("a belly").
Importance
Lewis Wolpert, pioneering developmental biologist in the field, has been credited for noting that "It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life."[2][11]
Model systems
Gastrulation is highly variable across the animal kingdom but has underlying similarities. Gastrulation has been studied in many animals, but some models have been used for longer than others. Furthermore, it is easier to study development in animals that develop outside the mother.
.Protostomes versus deuterostomes
The distinction between protostomes and deuterostomes is based on the direction in which the mouth (stoma) develops in relation to the blastopore. Protostome derives from the Greek word protostoma meaning "first mouth" (πρῶτος + στόμα) whereas Deuterostome's etymology is "second mouth" from the words second and mouth (δεύτερος + στόμα).[citation needed]
The major distinctions between deuterostomes and protostomes are found in
- Mouth/anus
- In protostome development, the first opening in development, the blastopore, becomes the animal's mouth.
- In deuterostome development, the blastopore becomes the animal's anus.
- Cleavage
- Protostomes have what is known as spiral cleavage which is determinate, meaning that the fate of the cells is determined as they are formed.
- Deuterostomes have what is known as radial cleavage that is indeterminate.
Sea urchins
Sea urchins have been important model organisms in developmental biology since the 19th century.[12] Their gastrulation is often considered the archetype for invertebrate deuterostomes.[13] Experiments along with computer simulations have been used to gain knowledge about gastrulation in the sea urchin. Recent simulations found that planar cell polarity is sufficient to drive sea urchin gastrulation.[14]
Germ layer determination
Sea urchins exhibit highly stereotyped cleavage patterns and cell fates. Maternally deposited
Cell internalization
In
Amphibians
The frog genus Xenopus has been used as a model organism for the study of gastrulation.[17]
Symmetry breaking
The sperm contributes one of the two
Germ layer determination
Specification of endoderm depends on rearrangement of maternally deposited determinants, leading to nuclearization of
Cell internalization
The dorsal lip of the blastopore is the mechanical driver of gastrulation. The first sign of invagination seen in the frog is the dorsal lip.[citation needed]
Cell signaling
In the frog, Xenopus, one of the signals is retinoic acid (RA).[22] RA signaling in this organism can affect the formation of the endoderm and depending on the timing of the signaling, it can determine the fate whether its pancreatic, intestinal, or respiratory. Other signals such as Wnt and BMP also play a role in respiratory fate of the Xenopus by activating cell lineage tracers.[22]
Amniotes
Overview
In
Symmetry breaking
In preparation for gastrulation, the embryo must become asymmetric along both the
Germ layer determination
The
During the early stages of development, the primitive streak is the structure that will establish
Cell internalization
In order for the cells to move from the
Cell signaling
There are certain signals that play a role in determination and formation of the three germ layers, such as FGF, RA, and Wnt.[22] In mammals such as mice, RA signaling can play a role in lung formation. If there is not enough RA, there will be an error in the lung production. RA also regulates the respiratory competence in this mouse model.[citation needed]
Cell signaling driving gastrulation
During gastrulation, the cells are differentiated into the ectoderm or
Gastrulation in vitro
There have been a number of attempts to understand the processes of gastrulation using in vitro techniques in parallel and complementary to studies in embryos, usually though the use of 2D[32][33][34] and 3D cell (Embryonic organoids) culture techniques[35][36][37][38] using embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs). These are associated with number of clear advantages in using tissue-culture based protocols, some of which include reducing the cost of associated in vivo work (thereby reducing, replacing and refining the use of animals in experiments; the 3Rs), being able to accurately apply agonists/antagonists in spatially and temporally specific manner[36][37] which may be technically difficult to perform during Gastrulation. However, it is important to relate the observations in culture to the processes occurring in the embryo for context.
To illustrate this, the guided differentiation of mouse ESCs has resulted in generating
In vitro fertilization occurs in a laboratory. The process of in vitro fertilization is when mature eggs are removed from the ovaries and are placed in a cultured medium where they are fertilized by sperm. In the culture the embryo will form.[40] 14 days after fertilization the primitive streak forms. The formation of the primitive streak has been known to some countries as "human individuality".[41] This means that the embryo is now a being itself, it is its own entity. The countries that believe this have created a 14-day rule in which it is illegal to study or experiment on a human embryo after the 14-day period in vitro. Research has been conducted on the first 14 days of an embryo, but no known studies have been done after the 14 days.[42] With the rule in place, mice embryos are used understand the development after 14 days; however, there are differences in the development between mice and humans.
See also
- Blastocyst
- Deuterostome
- Fate mapping
- Primitive node
- Invagination
- Neurulation
- Protostome
- Vegetal rotation
References
Notes
- ISBN 978-0134093413.
- ^ OCLC 945169933.
- ^ Mundlos 2009: p. 422
- ^ a b McGeady, 2004: p. 34
- ISBN 978-0-470-92351-1.
- ^ Hall, 1998: pp. 132-134
- ^ a b c d e Arnold & Robinson, 2009
- ^ Hall, 1998: p. 177
- ^ Gilbert, Scott F. (2000). "Figure 8.6, [Types of cell movements during...]". www.ncbi.nlm.nih.gov. Retrieved 11 May 2022.
- ^ Ereskovsky 2010: p. 236
- ISBN 978-0-486-46929-4
- .
- ISBN 978-0-87969-707-5.
- S2CID 210934521.
- ^ Hardin J D (1990). "Context-sensitive cell behaviors during gastrulation" (PDF). Semin. Dev. Biol. 1: 335–345.
- S2CID 39348233.
- ^ a b Gilbert, Scott F. (2000). "Axis Formation in Amphibians: The Phenomenon of the Organizer, The Progressive Determination of the Amphibian Axes". Developmental Biology. Sinauer Associates.
- ^ Gilbert, Scott F. (2000). "Figure 10.20, [Organization of a secondary axis...]". www.ncbi.nlm.nih.gov. Retrieved 1 June 2020.
- S2CID 12605303.
- PMID 16482093.
- ^ PMID 19575677.
- ^ a b Tam & Behringer, 1997
- ^ Catala, 2005: p. 1535
- ^ S2CID 138874.
- S2CID 244841366.
- ^ S2CID 758473.
- ^ PMID 19609969.
- PMID 16725136.
- PMID 18023726.
- S2CID 16552755.
- ^ PMID 25115237.
- ^ PMID 24973948.
- ^ PMID 27746044.
- ^ PMID 25371360.
- ^ bioRxiv 10.1101/051722.
- ^ bioRxiv 10.1101/104539.
- S2CID 52915553.
- PMID 28951435.
- ^ "In vitro fertilization (IVF) - Mayo Clinic". www.mayoclinic.org. Retrieved 2022-04-11.
- S2CID 207896932.
- S2CID 58643344.
Bibliography
- Arnold, Sebastian J.; S2CID 94174.
- Catala, Martin (2005). "Embryology of the Spine and Spinal Cord". In Tortori-Donati, Paolo; et al. (eds.). Pediatric Neuroradiology: Brain. Springer. ISBN 978-3-540-41077-5.
- Ereskovsky, Alexander V. (2010). The Comparative Embryology of Sponges. Springer. ISBN 978-90-481-8574-0.
- Gilbert, Scott F. (2010). Developmental Biology (Ninth ed.). Sinauer Associates. ISBN 978-0-87893-558-1.
- ISBN 978-0-412-78580-1.
- ISBN 978-0-521-55350-6.
- McGeady, Thomas A., ed. (2006). "Gastrulation". Veterinary embryology. Wiley-Blackwell. ISBN 978-1-4051-1147-8.
- Mundlos, Stefan (2009). "Gene action: developmental genetics". In Speicher, Michael; et al. (eds.). Vogel and Motulsky's Human Genetics: Problems and Approaches (4th ed.). Springer. ISBN 978-3-540-37653-8.
- Tam, Patrick P.L.; Behringer, Richard R. (1997). "Mouse gastrulation: the formation of a mammalian body plan". S2CID 14052942.
Further reading
- Baron, Margaret H. (2001). "Embryonic Induction of Mammalian Hematopoiesis and Vasculogenesis". In Zon, Leonard I. (ed.). Hematopoiesis: a developmental approach. Oxford University Press. ISBN 978-0-19-512450-7.
- Cullen, K.E. (2009). "embryology and early animal development". Encyclopedia of life science, Volume 2. Infobase. ISBN 978-0-8160-7008-4.
- Forgács, G.; Newman, Stuart A. (2005). "Cleavage and blastula formation". Biological physics of the developing embryo. Cambridge University Press. ISBN 978-0-521-78337-8.
- Forgács, G.; Newman, Stuart A. (2005). "Epithelial morphogenesis: gastrulation and neurulation". Biological physics of the developing embryo. Cambridge University Press. ISBN 978-0-521-78337-8.
- Hart, Nathan H.; Fluck, Richard A. (1995). "Epiboly and Gastrulation". In Capco, David (ed.). Cytoskeletal mechanisms during animal development. Academic Press. ISBN 978-0-12-153131-7.
- Knust, Elizabeth (1999). "Gastrulation movements". In Birchmeier, Walter; Birchmeier, Carmen (eds.). Epithelial Morphogenesis in Development and Disease. CRC Press. pp. 152–153. ISBN 978-90-5702-419-1.
- Kunz, Yvette W. (2004). "Gastrulation". Developmental biology of Teleost fishes. Springer. ISBN 978-1-4020-2996-7.
- Nation, James L., ed. (2009). "Gastrulation". Insect physiology and biochemistry. CRC Press. ISBN 978-0-8493-1181-9.
- Ross, Lawrence M.; Lamperti, Edward D., eds. (2006). "Human Ontogeny: Gastrulation, Neurulation, and Somite Formation". Atlas of anatomy: general anatomy and musculoskeletal system. Thieme. ISBN 978-3-13-142081-7.
- Sanes, Dan H.; et al. (2006). "Early embryology of metazoans". Development of the nervous system (2nd ed.). Academic Press. pp. 1–2. ISBN 978-0-12-618621-5.
- Stanger, Ben Z.; Melton, Douglas A. (2004). "Development of Endodermal Derivatives in the Lungs, Liver, Pancreas, and Gut". In Epstein, Charles J.; et al. (eds.). Inborn errors of development: the molecular basis of clinical disorders of morphogenesis. Oxford University Press. ISBN 978-0-19-514502-1.
