Exibir código-fonte para Genes controlling pattern formation in Drosophila embryogenesis

{| border="1"
|+ '''Maternal Anteroposterior Axis'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''dicephalic'' (dic) || Maternal || Abnormal position of nurse cells relative to oocyte || || Contributes to anteroposterior polarity of nurse cell oocyte complex
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| ''gurken'' (grk) || Oocyte || Eggs ventralized with dorsal appendages reduced or missing || Similar to vertebrate transforming growth factor alpha (TGF-α), ligand for torpedo || Establishes first posterior and then dorsal identity of ovarian follicle cells
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| ''spindle'' (spn) (several loci) || Maternal germ line || Disturbed anteroposterior polarity of oocyte || || Determination of prospective oocyte among cystocytes
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| ''torpedo'' (trp) || Ovarian follicle cells || Similar to ''grk'' || Receptor tyrosine kinase, receptor for ''grk'' || Same as ''grk''
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{| border="1"
|+ '''Maternal Anterior Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''bicoid'' (bcd) || mRNA transcribed in nurse cells and transported to anterior of oocyte. Translated during cleavage. Protein forms anteroposterior gradient. || Head and thorax replaced with mirror image of telson || Transcriptional regulator (homeodomain and paired repeat) || Activates ''hb'' transcription; acts as a morphogen on embryonic genes; expressed anteriorly
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| ''exuperantia'' (exu) || Testis and ovary || Reducion of head; defective gastrulation || RNA-binding protein || Needed to transport ''bcd'' mRNA from nurse cells to oocyte
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| ''hunchback'' (hb) || See '''Zygotic Anteroposterior Gap Class'''
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| ''staufen'' (stau) || Maternal germ line, emryonic central nervous system || Most abdominal segments missing, no pole cells, also head defects || Double-stranded RNA-binding protein || Required for ''bicoid'' mRNA localization and polar granule assembly
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| ''swallow'' (swa) || Maternal germ line || Reduction of head; cellularization defects || Rna-binding protein || Required for localization of ''bcd'' mRNA
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{| border="1"
|+ '''Maternal Posterior Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''cappuccino'' (capu) || Maternal || Abdominal segments A2-A7 missing; no pole cells || Putative transmembrane receptor || Required for polar granule assembly
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| ''nanos'' || Transcription in oocyte and nurse cells. Partial localization to polar granules. Only this localized mRNA is translated. || Absence of abdomen; pole cells normal || RNA-binding protein, translational repressor || Inhibits translation of maternal ''hb'' mRNA and hastens its destruction, hence allows activation of ''kni'' in posterior.
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| ''oskar'' (osk) || Maternal germ line || Similar to ''capu'' || || Required for polar granule assembly, localizes ''nos'' mRNA
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| '' pumilio'' (pum) || Transcription maternal. Protein probably localized to posterior || Most of abdomen missing; pole cells normal || RNA-binding protein || Recruits ''nos'' protein to ''hb'' mRNA
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| ''spire'' (spir) || Maternal || Similar to ''capu'' || Actin-binding protein || Required for polar granule assembly
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| ''staufen'' (stau) || See maternal anterior system
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| ''tudor'' (tud) || Male and female germ line || Similar to ''capu'' || || Required for pole cell formation
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| ''vasa'' (vas) || Transcription in nurse cells and oocyte; mRNA uniform in early embryo. Protein localized in posterior of oocyte, egg, and in pole cells. || Similar to ''capu'' || RNA helicase || Required for pole cell formation
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{| border="1"
|+ '''Maternal Terminal Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''NTF-1'' || || || Transcriptional inhibitor || Inhibits transcription of ''hkb'' and ''tll''
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| ''torso'' (tor) || Transcription in nurse cells. Transport to oocyte, where protein distributed uniformly in plasma membrane. || Absence of labrum, reduction of head skeleton, absence of A8 and telson; gain of function; suppression of segmentation in thorax and abdomen || Tyrosine kinase receptor, likely receptor for active ''trunk'' protein || Activates ''tll'' ''hkb'' by inhibiting ''NTF-1''
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| ''torsolike'' (tsl) || Protein secreted by anterior and posterior ovarian follicle cells probably associates with vitelline envelope near egg poles || Similar to ''tolr'' (loss of funct'''i'''on only) || Modifying protein || Generates active form of ''trunk'' near egg poles
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| ''Trunk'' (trk) || Maternal mRNA translated in early embryo, protein released into preivitelline space || Similar to ''tor'' || Secreted protein || Probably ligand of ''tor'', after processing by ''tsl''
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{| border="1"
|+ '''Zygotic Anteroposterior Gap Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''empty spiracles'' || Transcription during blastoderm 78-67% EL; later, in cells forming tracheal pits and spiracles || Defects in antennal segment, tracheal system || Transcriptional regulator (homeodomain) || Specifies procephalic segments
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| ''giant'' (gt) || Initial transcription at preblastoderm stage 82-60% and 33-0% EL; changes later || Defects in or absence of labrum, labium, and abdominal segments || Transcriptional regulator (Leucine zipper) || Activates ''Scr''; represses ''Kr''
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| ''huckebein'' (hkb) || Anterior and posterior ends of blastoderm || Defects in terminal body structures and gut || Transcriptional regulator (zinc finger domain) || Specifies terminal structures in concert with ''tll''
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| ''hunchback'' (hb) || Maternal mRNA initially uniform; protein forms anteroposterior gradient. Embryonic transcription 100-50% EL and 20-10% EL. Posterior domain long-lasting. || Embryonic: deletion of labium, thorax, aA7/pA8 (PS 13). No pure maternal effect, but if mother and sperm are ''hb''-, then deletion of all mouthparts and thoracic segments and A1-A3, with mirror duplication of abdomen. || Transcriptional regulator (zinc finger domain) || Represses ''kni''; represses ''Kr'' at high level and activates at low level; regulates ''eve''; regulates ''h'', ''run'', ''ftz''; activates ''Antp'' (with ''ftz''); represses ''Ubx''
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| ''knirps'' (kni) || Transcription starts at preblastoderm stage forming zone 45-30% EL. Ventral patch and narrow ring form in atnerior by cellular blastoderm stage. || Replacement of A1-A7 by single A-type segment || Transcriptional regulator (zinc finguer) || Represses ''Kr''; regulates ''h'', ''run'', ''eve'', ''ftz''; represses ''Abd-B'' and ''Antp''
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| ''Krüppel'' (Kr) || Transcription starts at preblastoderm stage in central zone, eventually expanding to 60-30% EL. Later also posterior patch and patch in head. || Purely embryonic. Head normal, deletion of thorax and A1-A5. Duplicated inverted A6. || Trancriptional regulator (zinc finguer) || Activates ''kni''; represses ''gt''; regulates ''eve''; regulates ''h'', ''run'', ''ftz''; represses ''Scr''; activates ''Antp''; represses ''Abd-B''
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| ''orthodenticle'' (otd) || Narrow band (75-92% EL) in anterior blastoderm || Defects in eyes and anterior head parts || Transcriptional regulator (homeodomain, paired domain) || Activated by ''bcd'' and ''tor'', ''otd'' - along with ''ems'' - specifies procephalic segments
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| ''tailless'' (tll) || Transcription in termini of preblastoderm embryo || Head skeleton reduced but labrum present. Hindgut, Malpighian tubules absent. || Transcriptional regulator (steroid receptor family) || Activates ''hb''; represses ''Kr''; represses ''kni''; activates ''h''
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{| border="1"
|+ '''Zygotic Pair-Rule Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''even-skipped'' (eve) || Transcription starts at preblastoderm stage; 7 stripes corresponding to parasegments 1, 3, 5, etc., by cellularization stage. Fades during gastrulation. || Abolishes segmentation, giving lawn of denticles. Weak alleles delete odd parasegments. || Transcriptional regulator (homeodomain) || Represses ''ftz'', ''odd'', ''run''; activates itself; activates ''en''; represses ''wg''; activates ''Dfd''
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| ''fushi tarazu'' (ftz) || Transcription starts at preblastoderm stage; 7 stripes corresponding to parasegments 2, 4, 6, etc., by cellularization. Fades during germ band extension. || Deletes even parasegments || Transcriptional regulator (homeodomain) || Activates itself; activates ''en''; activates ''Antp''; activates ''Ubx''; represses ''wg''
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| ''hairy'' (h) || Transcription starts at preblastoderm stage; 7 stripes + dorsal head patch by time of cellularization. Fades during gastrulation. || Range from deletion of odd parasegments to formation of lawn of denticles. Also loss of labral tooth. Other alleles give extra hairs in adult. || Transcriptional regulator (helix-loop-helix domain) || Represses ''run'', ''ftz''; activates ''eve''
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| ''paired'' (prd) || Transcription starts at preblastoderm stage; 8 stripes with dorsal head patch by cellularization. During germ band extension stripes 2-7 split and then fade. || Deletions about 1 segment wide starting in middle of denticle band affecting mainly odd abdominal segments || Transcriptional regulator (homeodomain) || Activates ''wg'', ''en''
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| ''runt'' (run) || Transcription starts at preblastoderm stage; 7 stripes. After cellularization, patter becomes single-segment stripes, which persist through germ band extension. || Deletions more than 1 segment wide centered on T2, A1, A3, A5, A7, with mirror duplication of what is left || Transcriptional regulator (novel) || Represses ''h'', ''eve''; activates ''ftz''
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{| border="1"
|+ '''Zygotic Segment Polarity Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''engrailed'' (en) || Transcription starts at blastoderm stage and produces 14 narrow stripes by extended germ band stage, marking the anterior of each parasegment. Expression in posterior compartments of larval imaginal discs || Ventral cuticle a continuous lawn of denticles. Less severe alleles delete even-numbered parasegments || Transcriptional regulator (homeodomain) || Maintains ''hh'' and indirectly ''wg'' activity; selector gene defining posterior compartment
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| ''frizzled'' (fz) || Various imaginal discs || Variable orientation of wing hairs, irregular ommatidia in eye || Seven-pass transmembrane receptor || Receptor for ''wg''
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| ''frizzled-2'' (fz-2) || Apparently redundant with ''fz'' 
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| ''hedgehog'' (hh) || Posterior compartments of larval segments and imaginal discs || Posterior compartment replaced with mirror image of anterior compartment || Secreted sinaling molecule (TGF-β super family) || Maintains ''wg'' and indirectly ''en''. defines source of segmental morphogen
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| ''patched'' (ptc) || In anterior compartments || Defects in segmentation and eye development || Multipass transmembrane protein || Parto of the receptor complex for ''hh''
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| ''smoothened'' (smo) || In anterior compartments || Defects in various tissues including epidermis, wing, and eye || G protein-associated transmembrane receptor || Part of the receptor complex for ''hh''; causes segregation of posterior from anterior compartmente cells
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| ''wingless'' (wg) || Transcription starts at blastoderm stage and produces 14 narrow stripes by extended germ band stage, marking the posterior of each parasegment. || Ventral cuticle a continuous lawn of denticles, indicating deletion of 3/4 of each segmental unit || Secreted signaling molecule (''Wnt'' family) || Maintains ''en''
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{| border="1"
|+ '''Homeotic Genes and Related Genes'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''abdominal A'' (abd-A) || Trancribed in PS 7-13 of extended germ band || Transforms PS 7-9 to PS 6 || Transcriptional regulator (homeodomain) || Represses ''Ubx''; activates ''wg'', ''dpp''; specifies a.p. body pattern
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| ''Abdominal B'' (Abd-B) || Transcribed in PS 10-14 of extended germ band || Transforms PS 10-14 to PS 9 || Transcriptional regulator (homeodomain) || Represses ''Ubx''; specifies a.p. body pattern
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| ''Antennapedia'' (Antp) || Transcription starts in blastoderm; mainly PS 4, also in posterior parasegments. Thoracic imaginal discs. || Transforms PS4, 5 to PS 3 || Transcriptional regulator (homeodomain) || Specifies a.p. body pattern
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| ''Deformed'' (Dfd) || Transcription in preblastoderm stage in PS 1; later also PS 0. Eye-antennal disc. || Deletion of mandibular and maxillary segments || Transcriptional regulator (homeodomain) || Activates itself; specifies a.p. body pattern
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| ''labial'' (lab) || Transcription in extended germ band anterior to cephalic furrow and in posterior midgut || Deletes labial derivatives || Transcriptional regulator (homeodomain) || Specifies a.p. body pattern
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| ''Polycomb-group'' (Pc-G) || || Multiple homeotic transformations || || Maintains inhibition of inactive homeotic genes
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| ''Sex combs reduced'' (Scr) || Transcription in PS 2 in blastoderm; later PS 3 epidermis and mesoderm, and abdominal ganglia || Transforms PS3 to PS 4 and PS2 to PS1 || Transcriptional regulator (homeodomain) || Specifies a.p. body pattern
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| ''trithorax-group'' (trx-G) || || Multiple homeotic transformations || || Maintains inhibition of active homeotic genes
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| ''Ultrabithorax'' (Ubx) || Transcrition starts in cellular blastoderm, mainly in PS 6, but at lower levels in PS5-13; more in even-numbered parasegments. Neuromeres; metathoracic discs. || Transforms PS 5, 6 to PS 4 || Transcriptional regulator (homeodomain) || Represses ''Scr''; represses ''Antp''; activates itself; activates ''wg'', ''dpp''; selector gene
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{| border="1"
|+ '''Maternal Dorsoventral System'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| '' cactus'' (cac) || Maternal; action in embryo || Ventralizing || Genetic regulator || Inhibits entry of ''dl'' protein to nuclei
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| ''dorsal'' (dl) || Transcription in nurse cells; uniform mRNA in oocyte and egg; ventral-dorsal gradient of protein in preblastoderm nuclei || Embryos become tubes of dorsal epidermis. Some haploinsufficient alleles. || Genetic regulator || Activates ''twi'', ''sna''; represses ''zen'', ''dpp''; morphogen for dorsoventral pattern
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| ''easter'' (ea) || Maternal, released from embryo into preivitelline space || Similar to ''dl''. Also weak ventralizing gain-of-function alleles. || Serine proteases || Activation of ''spz'' (''Tl'' ligand)
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| ''gastrulation defective'' (gd) || Maternal, released from embryo into perivitelline space || Similar to ''dl'' || Serine protease || Activation of ''spz'' (''Tl'' ligand)
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| ''gurken'' (grk) || Maternal; needed in oocyte || Ventralizing; affects eggshell and embryo || Growth factor-like || Ligand for top protein; dorsalizing signal from oocyte
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| ''nudel'' (ndl) || Maternal; needed in follicle cells || Similar to ''dl'' || Protease activity || Contributes to ventral polarizing activity
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| ''pelle'' (pll) || Maternal, acts in embryo || Similar to ''dl'' || Protein kinase || Signal transduction from ''Tl'' to ''cac''
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| ''pipe'' (pip) || Maternal; needed in follicle cells || Similar to ''dl'' || Glycosaminoglycan-modifying enzyme || Localized contribution to ventral polarizing activity
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| ''snake'' (snk) || Maternal, released from embryo into perivitelline space || Similar to ''dl'' || Serine protease || Activation of ''spz'' (''Tl'' ligand)
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| ''spätzle'' (spz) || Maternal, released from embryo into perivitelline space || Similar to ''dl'' || || Ligand for ''Tl'' protein
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| ''Toll'' (Tl) || Maternal; uniform distribution of protein in egg plasma membrane || Similar to ''dl''. Gain-of-function alleles ventralize, producing denticle belts all around. || Receptor tyrosine kinase || Activated ventrally by ''spz''; releases ''dl'' from ''cac'', permits ''dl'' to enter nucleus
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| ''torpedo'' (top) || Maternal; needed in follicle cells || Similar to ''grk'' || Growth factor receptor || Receptor for ''grk'', inhibits ''pip'', thus orienting ventral polarizing activity.
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| ''tube'' (tube) || Maternal; acts in embryo || Similar to ''dl'' || Adapter protein || Signal transduction from ''Tl'' to ''cac''
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| ''windbeutel'' (wbl) || Maternal; needed in follicle cells || Similar to ''dl'' || Enzyme associated with endoplasmic reticulum || Contributes to ventral polarizing activity.
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{| border="1"
|+ '''Zygotic Dorsoventral Class'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''decapentaplegic'' (dpp) || Transcription in preblastoderm on dorsal side, curling around to ventral at poles. (see also '''Compartment-Related Genes''') || Loss of amnioserosa and reduction of dorsal epidermis. Viable alleles produce multiple defects in imaginal disc derivatives. || Signaling molecule (TGF-β homologue) || Forms morphogen gradient with maximum dorsally. Promotes amnioserosa and epidermis; inhibits neurogenesis
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| ''short gastrulation'' (sog) || Protein synthesized blastoderm cells in ventral || Dorsalizes embryo || Plasma membrane protein || '''antagonizes''' ''dpp''; specifies d.v. pattern
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| ''snail'' (sna) || Transcription in mid-ventral strip of prospective mesoderm || Loss of mesoderm || Transcriptional regulator (zinc finger domain) || Inhibits expression of other d.v. patterning genes in prospective mesoderm.
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| ''tolloid'' (tld) || Released from blastoderm cells into extracellular space || Ventralizes embryo || Metalloprotease || Cleaves extracellular domain of ''sog'', especially in presence of ''dpp''; specifies d.v. pattern
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| ''twist'' (twi) || Transcription in mid-ventral strip of prospective mesoderm and mesectoderm || Loss of mesoderm || Transcriptional regulator (basic helix-loop-helix domain) || Specifies dorsoventral pattern
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| ''zerknüllt'' (zen) || Transcription in preblastoderm stage on dorsal side || Loss of amnioserosa and optic lobe || Transcriptional regulator (homeodomain) || Promotes amnioserosa formation
|}

{| border="1"
|+ '''Compartment-Related and Other Genes'''
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! Gene !! Expression Pattern !! Mutant Phenotype !! Molecular Nature !! Developmental Function
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| ''Achaete'' (Ac) || Proneural cells, prospective sensory bristles || Lack of sensory bristles and neurons || Transcriptional regulator (bHLH domain) || Many functions, incl. patterning around d.v. compartment boundary in wing
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| ''apterous'' (ap) || Dorsal compartments of wing and haltere discs || Wings and halteres missing || Transcriptional regulator (homeodomain) || Required for wing (haltere) outgrowth; selector gene
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| ''cubitus interruptus'' (ci) || Anterior compartment of each segment || Disturbed segmentation || Transcriptional regulator (zinc finger domain) || Activates ''wg'' and ''dpp'' in response to ''hh'' signaling
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| ''decapentaplegic'' (dpp) || In strip of cells anterior to a.p. compartment boundary (see also '''Zygotic Dorsoventral Class''') || Abnormal wing patterns || Secreted protein (TGF-β superfamily) || Morphogen for anteroposterior pattern of wing and haltere
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| ''Distalless'' (Dll) || Expressed around leg dorsoventral compartment boundary || Loss of legs and antennae || Transcriptional regulator (homeodomain) || Required for outgrowth of legs and antennae
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| ''fringe'' (fng) || Dorsal wing and haltere compartments || Loss of wings and halteres || Secreted protein || Juxtaposition of cells with and without ''fringe'' activates ''wg+''
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| ''hedgehog'' (hh) || see '''Zygotic Segment Polarity Class'''
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| ''optomotor-blind'' (omb) || Prospective CNS and epidermal regions || || Transcriptional regulator || Target of ''dpp'' in patterning of wing and abdominal segments
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| ''scute'' (sc) || Similar to ''Achaete''
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| ''spalt'' (sal) || In endoderm and parts of wing imaginal disc || || Transcriptional regulator (zinc finger domain) || Target of ''dpp'' in wing patterning
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| ''vestigial'' (vg) || In prospective appendages of wing and haltere imaginal discs || Loss of wings and halteres || Putative transcriptional regulator || Specification of wing and haltere as opposed to thorax
|}

== Ver também ==
* [[Biologia III]]
* [[Carlos Eduardo Winter]]
* [[Projeto Biologia do Desenvolvimento]]

[[Categoria: Projetos da Wikoleculares]]