Bicoid
| Bicoid ( Drosophila melanogaster ) | ||
|---|---|---|
| Mass / length primary structure | 494 amino acids | |
| Isoforms | 5 | |
| Identifier | ||
| Gene name (s) | bcd (FlyBase) | |
| External IDs | ||
Bicoid is a protein of the model organism fruit fly ( Drosophila melanogaster ) and other dipteran species. It is a transcription factor that plays an important role in cell differentiation in the early development of germs ( embryogenesis ). Bicoid or its gradient is important for the formation of the anterior-posterior axis and the body segmentation during embryogenesis. The name comes from a mutant whose gene product gives rise to embryos with two tail parts but no head.
The egg cell contains maternal bicoid mRNA at the future front end of the animal , which is fixed there in a kind of cap. After fertilization, there is initially no translation of the nucleus genome, but translation of these maternal m-RNAs ( maternal effect genes ) and the bicoid protein is produced . Accordingly, the highest bicoid concentration is found in the front (anterior) and this decreases in the rear (posterior). A concentration gradient arises because the embryo does not yet have any cell membranes ( syncytium ) and the protein diffuses freely . The bicoid protein now induces the activity of 3 gene classes as a gene cascade, namely gap genes one after the other , these in turn pair rule genes and segment polarity genes . As soon as the segments of the embryo are formed, the homeotic genes ultimately determine the role of the individual segments in the future animal body. At the point with the highest bicoid concentration, the fly's head is ultimately created. Via this cascade, the maternal bicoid gene also indirectly serves as an activator for the even skipped ( eve ) gene and the fushi-tarazu gene, i.e. those genes that control the division of the insect's body into different segments.
See also
- The work of the Nobel Prize winner Nüsslein-Volhard
- Drosophila
- Differentiation (biology)
Individual evidence
swell
- Bicoid in the Flybase (eng.)
- Transcription factors and bicoid on ZUM
- R.Wehner; W. Gehring: Zoology. 24th edition, Thieme Verlag, Stuttgart, 2007, p. 241 ff. ISBN 978-3-13-367424-9
- WKPurves, D, Sadava et al: Biologie, Spektrum Vlg. 2006, p. 484 ff. ISBN 978-3-8274-1630-8