Halloween genes

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20-Hydroxyecdysone is synthesized under the catalytic influence of the cytochrome P450 enzyme encoded by the shade gene.

The Halloween genes are a group of genes that code for cytochrome P450 enzymes that are involved in the biosynthesis of ecdysteroids . They are involved in the formation of ecdysone and ecdysterone from cholesterol and thus play an important role in the molting process of insects. The individual genes in this group are called spook , spookier , phantom (or phm ), disembodied (or dib ), shadow (or sad ) and shade . These genes were first studied in the early 1980s by the research groups of the later Nobel Prize winners Eric F. Wieschaus and Christiane Nüsslein-Volhard on the fruit fly Drosophila melanogaster . The name refers to a series of deadly mutations that hinder the correct formation of the exoskeleton . It could be shown that if one of these genes were mutated, the test animals died before the exoskeleton was formed.

Single descriptions

The spook gene coding for the enzyme CYP307A1 which in the Prothorax -Drüse expressed is. Together with CYP307A2 , the gene product of spookier , it mediates the formation of Δ 4 -diketol from 7-dehydrocholesterol.

The phantom gene codes for microsomal 25-hydroxylase ( CYP306A1 ). This gene is particularly strongly expressed in the corpora allata of Drosophila larvae. The enzyme CYP306A1 formed converts 2,22,25dE-ketodiol to 2,22dE-ketotriol.

The disembodied gene codes for the cytochrome P450 enzyme CYP302A1 . CYP302A1 catalyzes the addition of a hydroxy group at position C-22 of 2.22, dE-ketotriol, thereby forming 2-deoxyecdysone. Mutations in this gene lead to a disruption of the formation of the cuticle and to further severe disorders of morphogenesis .

The shadow gene codes for CYP315A1 and catalyzes the synthesis of ecdysone from 2-deoxyecdysone.

The shade gene codes for the cytochrome P450 enzyme CYP314A1 , which catalyzes the addition of a hydroxy group at position C-20 in ecdysone, thereby forming 20-hydroxyecdysone . This is the final step in the biosynthesis of this hormone.

Individual evidence

  1. ↑ a b c d Gilbert LI .: Drosophila is an inclusive model for human diseases, growth and development . In: Molecular and Cellular Endocrinology . 293, No. 1-2, 2008, pp. 25-31. doi : 10.1016 / j.mce.2008.02.009 . PMID 18374475 .
  2. ↑ Namiki T, Niwa R, Sakudoh T, Shirai K, Takeuchi H, Kataoka H .: Cytochrome 450 CYP307A1 / Spook: A regulator for ecdysone synthesis in insects . In: Biochemical and Biophysical Research Communications . 337, No. 1, 2005, pp. 367-74. doi : 10.1016 / j.bbrc.2005.09.043 . PMID 16188237 .
  3. ↑ Warren JT, Petryk A, Marqués G, Parvy JP, Shinoda T, Itoyama K, Kobayashi J, Jarcho M, Li Y, O'Connor MB, Dauphin-Villemant C, Gilbert LI .: Phantom encodes the 25-hydroxylase of Drosophila melanogaster and Bombyx mori: a P 450 enzyme critical in ecdysone biosynthesis . In: Insect Biochemistry and Molecular Biology . 34, No. 9, 2004, pp. 991-1010. doi : 10.1016 / j.ibmb.2004.06.009 . PMID 15350618 .
  4. ↑ Gilbert LI .: Halloween genes encode P 450 enzymes that mediate steroid hormone biosynthesis in Drosophila melanogaster . In: Molecular and Cellular Endocrinology . 215, No. 1-2, 2004, pp. 1-10. doi : 10.1016 / j.mce.2003.11.003 . PMID 15026169 .
  5. ↑ Chávez VM, Marqués G, Delbecque JP, Kobayashi K, Hollingsworth M, Burr J, Natzle JE, O'Connor MB .: The Drosophila disembodied gene controls late embryonic morphogenesis and codes for a cytochrome P 450 enzyme that regulates embryonic ecdysone levels . In: Development . 127, No. 19, 2000, pp. 4115-26. PMID 10976044 .
  6. ↑ Petryk A, Warren JT, Marques G, Jarcho MP, Gilbert LI, Kahler J, Parvy JP, Li YT, Dauphin-Villemant C, O'Connor MB: Shade is the Drosophila P 450 enzyme that mediates the hydroxylation of ecdysone to the steroid insect molting hormone 20-hydroxyecdysone . In: Proceedings of the National Academy of Sciences of the United States of America . 100, No. 24, 2003, pp. 13773-78. doi : 10.1073 / pnas.2336088100 .