fbpx
Wikipedia

Orthodenticle

January 01, 1970

Orthodenticle (otd) is a homeobox gene found in Drosophila that regulates the development of anterior patterning, with particular involvement in the central nervous system function and eye development.[1] It is located on the X chromosome.[1] The gene is an ortholog of the human OTX1/OTX2 gene.[2]

Function edit

During embryonic Drosophila development, otd is required for the head and ventral midline to develop correctly. In the larval stage, otd is expressed in specific sac-like epithelial structures known as imaginal discs that later give rise to external structures of the head and thorax. Particularly, otd is required for the development of the dorsal region of the adult Drosophila head, that forms from the fusion of two eye-antennal discs. Distribution of the otd protein occurs along a concentration of the imaginal disc primordia for these head structures such that different levels of otd expression are required for differential mediolateral subdomains to be established.[3] In Drosophila, the function of otd as an essential factor in anterior pattern formation has been replaced by Bicoid, another homeodomain protein [4] which is involved in anterior patterning such that bcd mRNA is sequestered at the anterior pole of the mature oocyte. In the absence of bcd, all anterior structures of the embryo including the cephalic and thoracic segments fail to develop, and duplications of posterior structures are observed instead.[4]

Additionally, otd is involved in development of all eight photoreceptors of adult Drosophila in each of their ~700 individual eye units, known as ommatidia[5] and their proximal-distal distribution in the eye.[6] The two types of photoreceptors, outer (OPRs) and inner (IPRs), are distinguished through their function and anatomy such that OPRs have six neurons that respond to dim light conditions and are important for motion detection, while IPRs have two neurons that differentiate colour.[5] OPRs possess light-gathering apical surfaces called rhabdomeres, and otd is required for rhabdomere morphogenesis. Rapid expression of otd in all OPRs and IPRs is found following neuronal cell specification in the late larval stage and persists through photoreceptor differentiation. In later development of pupation through to adulthood, otd activates light detecting rhodopsin proteins Rh3 and Rh5 in IPRs while repressing Rh6 in OPRs.

Regulation edit

Embryo edit

In the anterior cap region of the syncytial blastoderm, which has non-segregated nuclei along the periphery of the blastoderm, bicoid in low concentrations is sufficient to activate otd expression through an enhancer located upstream of the otd gene.[7][8][9] Later, in the cellular blastoderm, which has all nuclei along the periphery separated in individual cells with their own cell membrane, otd expression is limited to a dorsal and anterior band due to repression of bicoid by torso, hunchback, and dorsal.[7][8][9] Torso and hunchback expression represses otd expression in the anterior most region of the blastoderm while dorsal expression represses expression in the ventral region.[1][7] Groucho-independent repression of otd by runt, a pair-rule gene, has also been observed in the anterior and posterior regions of the syncytial and cellular blastoderm.[10]

Ocelliless edit

Ocelliless (oc) is a general mutation in the otd gene locus in Drosophila,[11] which results in a loss of ocelli: the three photoreceptor organs located on the anterior region of Drosophila heads [1] Two alleles oc1 and ocγa1, are caused by lesions downstream of the last exon in otd which showed enhancer activity.[11] Another characteristic of the oc phenotype is the abnormal or deleted bristles in the ocellus region,[12] which relates back to the wild type otd gene’s role in mediating anterior patterning.[4] The same oc phenotype is found in loss-of-function epidermal growth factor receptor (EGFR) alleles and RNAi knockdown pointed (pnt) mutants [13]

The effect of oc on ocelli can be complemented by otduvi, another hypomorphic allele of the otd gene. otduvi/oc heterozygotes shows no ocellar phenotype or photoreceptor (R cell) phenotype, a phenotype that is related with otduvi allele.[6]

The Ocelliless mutant phenotype is not limited to loss of ocelli only. It has a role in disrupting oogenesis, where the inner and outer layer of the chorion in oc mutant eggs separate from one another leaving space for debris that is not seen in wild type otd, and disrupting reproductive capabilities, where female flies homozygous for the oc mutation are sterile.[14]

References edit

  1. ^ a b c d Finkelstein R, Smouse D, Capaci TM, Spradling AC, Perrimon N (July 1990). "The orthodenticle gene encodes a novel homeo domain protein involved in the development of the Drosophila nervous system and ocellar visual structures". Genes & Development. 4 (9): 1516–1527. doi:10.1101/gad.4.9.1516. PMID 1979296.
  2. ^ Leuzinger S, Hirth F, Gerlich D, Acampora D, Simeone A, Gehring WJ, Finkelstein R, Furukubo-Tokunaga K, Reichert H (April 1998). "Equivalence of the fly orthodenticle gene and the human OTX genes in embryonic brain development of Drosophila". Development. 125 (9): 1703–1710. doi:10.1242/dev.125.9.1703. PMID 9521908.
  3. ^ Royet J, Finkelstein R (November 1995). "Pattern formation in Drosophila head development: the role of the orthodenticle homeobox gene" (PDF). Development. 121 (11): 3561–72. doi:10.1242/dev.121.11.3561. PMID 8582270.
  4. ^ a b c Datta RR, Ling J, Kurland J, Ren X, Xu Z, Yucel G, Moore J, Shokri L, Baker I, Bishop T, Paolo S, Levina R, Bulyk ML, Johnstron Jr RJ, Small S (May 2018). "A feed-forward relay integrates the regulatory activities of Bicoid and Orthodenticle via sequential binding to suboptimal sites". Genes & Development. 32 (9–10): 723–736. doi:10.1101/gad.311985.118. PMC 6004077. PMID 29764918. S2CID 21727027.
  5. ^ a b McDonald EC, Xie B, Workman M, Charlton-Perkins M, Terrel DA, Reischl J, Wimmer EA, Gebelein BA, Cook TA (November 2012). "Separable transcriptional regulatory domains within Otd control photoreceptor terminal differentiation events". Developmental Biology. 347 (1): 122–132. doi:10.1016/j.ydbio.2010.08.016. PMC 2969183. PMID 20732315.
  6. ^ a b Vandendries ER, Johnson D, Reinke R (January 1996). "orthodenticle Is Required for Photoreceptor Cell Development in the Drosophila Eye". Developmental Biology. 173 (1): 243–255. doi:10.1006/dbio.1996.0020. PMID 8575625.
  7. ^ a b c Gao Q, Wang Y, Finkelstein R (May 1996). "orthodenticle regulation during embryonic head development in Drosophila". Mechanisms of Development. 56 (1): 3–15. doi:10.1016/0925-4773(96)00504-7. PMID 8798143. S2CID 16431692.
  8. ^ a b Gao Q, Finkelstein R (September 1998). "Targeting gene e expression to the head: The drosophila orthodenticle gene is a direct target of the bicoid gene". Development. 125 (21): 4185–4193. doi:10.1242/dev.125.21.4185. PMID 9753673.
  9. ^ a b Mazumdar A, Mazumdar M (October 2022). "How one becomes many: Blastoderm cellularization in Drosophila melanogaster". BioEssays. 24 (11): 1012–1022. doi:10.1002/bies.10184. PMID 12386932. S2CID 45642558.
  10. ^ Tsai CC, Krame SG, Gergen JP (December 1998). "Pair-rule gene runt restricts orthodenticle expression to the presumptive head of the drosophila embryo". Developmental Genetics. 23 (1): 35–44. doi:10.1002/(SICI)1520-6408(1998)23:1<35::AID-DVG4>3.0.CO;2-7. PMID 9706692.
  11. ^ a b Blanco J, Seimiya M, Pauli T, Reichert H, Gehring WJ (May 2009). "Wingless and Hedgehog signaling pathways regulate orthodenticle and eyes absent during ocelli development in Drosophila". Developmental Biology. 329 (1): 104–115. doi:10.1016/j.ydbio.2009.02.027. PMID 19268449.
  12. ^ Fichelson P, Brigui A, Pichaud F (May 2012). "Orthodenticle and Kruppel homolog 1 regulate Drosophila photoreceptor maturation". Proceedings of the National Academy of Sciences. 109 (20): 7893–7898. Bibcode:2012PNAS..109.7893F. doi:10.1073/pnas.1120276109. PMC 3356647. PMID 22547825.
  13. ^ Jean-Guillaume CB, Kumar JP (May 2022). "Development of the ocellar visual system in Drosophila melanogaster". The FEBS Journal. 289 (23): 7411–7427. doi:10.1111/febs.16468. PMC 9805374. PMID 35490409. S2CID 248477548.
  14. ^ Johnson CC, King RC (December 1974). "Oogenesis in the ocelliless mutant of Drosophila melanogaster Meigen (Diptera: Drosophilidae)". International Journal of Insect Morphology and Embryology. 3 (3–4): 385–395. doi:10.1016/0020-7322(74)90032-4.

January 01, 1970
orthodenticle, homeobox, gene, found, drosophila, that, regulates, development, anterior, patterning, with, particular, involvement, central, nervous, system, function, development, located, chromosome, gene, ortholog, human, otx1, otx2, gene, contents, functi. Orthodenticle otd is a homeobox gene found in Drosophila that regulates the development of anterior patterning with particular involvement in the central nervous system function and eye development 1 It is located on the X chromosome 1 The gene is an ortholog of the human OTX1 OTX2 gene 2 Contents 1 Function 2 Regulation 2 1 Embryo 3 Ocelliless 4 ReferencesFunction editDuring embryonic Drosophila development otd is required for the head and ventral midline to develop correctly In the larval stage otd is expressed in specific sac like epithelial structures known as imaginal discs that later give rise to external structures of the head and thorax Particularly otd is required for the development of the dorsal region of the adult Drosophila head that forms from the fusion of two eye antennal discs Distribution of the otd protein occurs along a concentration of the imaginal disc primordia for these head structures such that different levels of otd expression are required for differential mediolateral subdomains to be established 3 In Drosophila the function of otd as an essential factor in anterior pattern formation has been replaced by Bicoid another homeodomain protein 4 which is involved in anterior patterning such that bcd mRNA is sequestered at the anterior pole of the mature oocyte In the absence of bcd all anterior structures of the embryo including the cephalic and thoracic segments fail to develop and duplications of posterior structures are observed instead 4 Additionally otd is involved in development of all eight photoreceptors of adult Drosophila in each of their 700 individual eye units known as ommatidia 5 and their proximal distal distribution in the eye 6 The two types of photoreceptors outer OPRs and inner IPRs are distinguished through their function and anatomy such that OPRs have six neurons that respond to dim light conditions and are important for motion detection while IPRs have two neurons that differentiate colour 5 OPRs possess light gathering apical surfaces called rhabdomeres and otd is required for rhabdomere morphogenesis Rapid expression of otd in all OPRs and IPRs is found following neuronal cell specification in the late larval stage and persists through photoreceptor differentiation In later development of pupation through to adulthood otd activates light detecting rhodopsin proteins Rh3 and Rh5 in IPRs while repressing Rh6 in OPRs Regulation editEmbryo edit In the anterior cap region of the syncytial blastoderm which has non segregated nuclei along the periphery of the blastoderm bicoid in low concentrations is sufficient to activate otd expression through an enhancer located upstream of the otd gene 7 8 9 Later in the cellular blastoderm which has all nuclei along the periphery separated in individual cells with their own cell membrane otd expression is limited to a dorsal and anterior band due to repression of bicoid by torso hunchback and dorsal 7 8 9 Torso and hunchback expression represses otd expression in the anterior most region of the blastoderm while dorsal expression represses expression in the ventral region 1 7 Groucho independent repression of otd by runt a pair rule gene has also been observed in the anterior and posterior regions of the syncytial and cellular blastoderm 10 Ocelliless editOcelliless oc is a general mutation in the otd gene locus in Drosophila 11 which results in a loss of ocelli the three photoreceptor organs located on the anterior region of Drosophila heads 1 Two alleles oc1 and ocga1 are caused by lesions downstream of the last exon in otd which showed enhancer activity 11 Another characteristic of the oc phenotype is the abnormal or deleted bristles in the ocellus region 12 which relates back to the wild type otd gene s role in mediating anterior patterning 4 The same oc phenotype is found in loss of function epidermal growth factor receptor EGFR alleles and RNAi knockdown pointed pnt mutants 13 The effect of oc on ocelli can be complemented by otduvi another hypomorphic allele of the otd gene otduvi oc heterozygotes shows no ocellar phenotype or photoreceptor R cell phenotype a phenotype that is related with otduvi allele 6 The Ocelliless mutant phenotype is not limited to loss of ocelli only It has a role in disrupting oogenesis where the inner and outer layer of the chorion in oc mutant eggs separate from one another leaving space for debris that is not seen in wild type otd and disrupting reproductive capabilities where female flies homozygous for the oc mutation are sterile 14 References edit a b c d Finkelstein R Smouse D Capaci TM Spradling AC Perrimon N July 1990 The orthodenticle gene encodes a novel homeo domain protein involved in the development of the Drosophila nervous system and ocellar visual structures Genes amp Development 4 9 1516 1527 doi 10 1101 gad 4 9 1516 PMID 1979296 Leuzinger S Hirth F Gerlich D Acampora D Simeone A Gehring WJ Finkelstein R Furukubo Tokunaga K Reichert H April 1998 Equivalence of the fly orthodenticle gene and the human OTX genes in embryonic brain development of Drosophila Development 125 9 1703 1710 doi 10 1242 dev 125 9 1703 PMID 9521908 Royet J Finkelstein R November 1995 Pattern formation in Drosophila head development the role of the orthodenticle homeobox gene PDF Development 121 11 3561 72 doi 10 1242 dev 121 11 3561 PMID 8582270 a b c Datta RR Ling J Kurland J Ren X Xu Z Yucel G Moore J Shokri L Baker I Bishop T Paolo S Levina R Bulyk ML Johnstron Jr RJ Small S May 2018 A feed forward relay integrates the regulatory activities of Bicoid and Orthodenticle via sequential binding to suboptimal sites Genes amp Development 32 9 10 723 736 doi 10 1101 gad 311985 118 PMC 6004077 PMID 29764918 S2CID 21727027 a b McDonald EC Xie B Workman M Charlton Perkins M Terrel DA Reischl J Wimmer EA Gebelein BA Cook TA November 2012 Separable transcriptional regulatory domains within Otd control photoreceptor terminal differentiation events Developmental Biology 347 1 122 132 doi 10 1016 j ydbio 2010 08 016 PMC 2969183 PMID 20732315 a b Vandendries ER Johnson D Reinke R January 1996 orthodenticle Is Required for Photoreceptor Cell Development in the Drosophila Eye Developmental Biology 173 1 243 255 doi 10 1006 dbio 1996 0020 PMID 8575625 a b c Gao Q Wang Y Finkelstein R May 1996 orthodenticle regulation during embryonic head development in Drosophila Mechanisms of Development 56 1 3 15 doi 10 1016 0925 4773 96 00504 7 PMID 8798143 S2CID 16431692 a b Gao Q Finkelstein R September 1998 Targeting gene e expression to the head The drosophila orthodenticle gene is a direct target of the bicoid gene Development 125 21 4185 4193 doi 10 1242 dev 125 21 4185 PMID 9753673 a b Mazumdar A Mazumdar M October 2022 How one becomes many Blastoderm cellularization in Drosophila melanogaster BioEssays 24 11 1012 1022 doi 10 1002 bies 10184 PMID 12386932 S2CID 45642558 Tsai CC Krame SG Gergen JP December 1998 Pair rule gene runt restricts orthodenticle expression to the presumptive head of the drosophila embryo Developmental Genetics 23 1 35 44 doi 10 1002 SICI 1520 6408 1998 23 1 lt 35 AID DVG4 gt 3 0 CO 2 7 PMID 9706692 a b Blanco J Seimiya M Pauli T Reichert H Gehring WJ May 2009 Wingless and Hedgehog signaling pathways regulate orthodenticle and eyes absent during ocelli development in Drosophila Developmental Biology 329 1 104 115 doi 10 1016 j ydbio 2009 02 027 PMID 19268449 Fichelson P Brigui A Pichaud F May 2012 Orthodenticle and Kruppel homolog 1 regulate Drosophila photoreceptor maturation Proceedings of the National Academy of Sciences 109 20 7893 7898 Bibcode 2012PNAS 109 7893F doi 10 1073 pnas 1120276109 PMC 3356647 PMID 22547825 Jean Guillaume CB Kumar JP May 2022 Development of the ocellar visual system in Drosophila melanogaster The FEBS Journal 289 23 7411 7427 doi 10 1111 febs 16468 PMC 9805374 PMID 35490409 S2CID 248477548 Johnson CC King RC December 1974 Oogenesis in the ocelliless mutant of Drosophila melanogaster Meigen Diptera Drosophilidae International Journal of Insect Morphology and Embryology 3 3 4 385 395 doi 10 1016 0020 7322 74 90032 4 Retrieved from https en wikipedia org w index php title Orthodenticle amp oldid 1140401182, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.