Genes {development genes} can control development. Serotonin affects early embryo development, and mother supplies it before fetus can make it.
Genes {histone deacetylase 4 gene} (HDAC4) can regulate muscle and bone development and maintain rod and bipolar cells.
Genes {early-response gene} {immediate early gene} can respond first to stimulation and then trigger later changes.
Homeobox and other genes {master control gene} can start gene-expression chains.
Stickleback-fish gene {Pitx1 gene} products can affect pelvic fin and other structures.
Gene {Notch gene} products can activate signaling pathways and regulate whether neural precursors become neurons or glia. Enzymes cleave Notch and APP transmembrane proteins in membrane plane {regulated intramembrane proteolysis}, to liberate cytosolic fragments, which enter cell nucleus to control gene transcription. Regulated intramembrane proteolysis is similar from bacteria to humans.
Gene {Bmi-1 gene} products can activate signaling pathways.
Gene {Wnt gene} products can activate signaling pathways.
Homeodomain binding proteins have one helix in DNA major groove and another helix across DNA that contacts other proteins. Fruitfly homeotic genes {homeobox gene} control head, jaws, teeth, thorax, and abdomen development and contain 180-base control regions {homeobox} that have helix-turn-helix {homeodomain} sequences, which are in many development genes. Regulatory region has 200,000 bases total.
retinoic acid
Extracellular-fluid retinoic acid controls homeotic-gene expression by binding to cell receptors and builds spinal cord, hindbrain, eye, and limbs. Low concentrations start gene expression at forebrain, and then higher concentrations start gene expression in sequence down to tail.
hormone
Thyroid hormone has similar receptors and controls gene expression.
Human Hox gene and other homeobox development genes {homeotic gene} can have sequences {homeotic series} along chromosomes. First gene is for mouth/nose, and last gene is for tail. Earliest homeobox genes were 1, 2/3, 4, 5, 6/7/8, and 9/10/11/12/13, in sequence. Fruit flies have 1, 2/3, 4, 5, 6, 7, 8, and 9/10/11/12/13. Fruit flies have non-homeobox region of DNA between 6 and 7. Chordates have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13. Vertebrates have chordate-set variants on four different chromosomes.
Mammal genes {BF gene} can control gut, liver, and lungs. BF genes are similar to forkhead genes. BF-1 enlarges nasal retina and dorsal forebrain and is where neurons start dividing {germinal zone} before migrating. BF-2 enlarges ventral forebrain and temporal retina.
Mammal Emx-1 and Emx-2 genes {Emx gene} enlarge cerebrum, including corpus callosum. Fruitfly genes {empty spiracles gene} are similar.
Fruitfly genes {engrailed gene} can have homeoboxes but not be in homeotic gene sequence for body development. In most vertebrates, En-1 and En-2 genes, similar to engrailed gene, control midbrain and cerebellum growth.
Fruitfly genes {forkhead gene} can develop gut beginning and end.
Vertebrate genes {Hox gene} can be similar to fruitfly homeobox genes. If Hox genes are missing, symptoms are similar to DiGeorge congenital disease. Hox-b1, Hox-b2, Hox-b3, Hox-b4, and Hox-b5 genes enlarge hindbrain from third rhombomere down.
Genes {Lim-1 gene} can enlarge forebrain, midbrain, cerebellum, and first two or three hindbrain rhombomeres.
Genes {Otx gene} can affect brain development. Otx2 protein is for head development in embryo. After birth, it signals eye coordination.
Genes {Pax6 gene} can affect halteres balancing-wing development. Pax genes also affect eye and brain development.
Fruitfly genes {tailless gene} can develop gut beginning and end. Tailless gene enlarges forebrain, retina, and olfaction receptors.
At fertilization, genes {maternal-effect gene} from mother can code for transcription factors that establish front-to-back and top-to-bottom embryo polarity: bicoid protein, nanos protein, and dorsal gene protein transcription factor.
Proteins {bicoid protein transcription factor}, at only one pole, can make top-to-bottom gradient across embryo {morphogen, bicoid}. Nanos is at one pole, and bicoid is at other pole.
Proteins {nanos protein transcription factor}, at only one pole, can make top-to-bottom gradient across embryo. Nanos is at one pole, and bicoid is at other pole.
Maternal-effect follicle-cell genes can code for transcription factors {dorsal gene protein transcription factor} that establish front-to-back embryo polarity. Factor is similar to rel protein and NF-kappaB. Factor concentrates in cell nucleus ventrally, and cytoplasm dorsally, in all embryo cells. Cactus gene and Toll gene can partition dorsal-gene-protein transcription factor to these cell locations.
After first cell divisions, genes {gap gene} {hunchback gene} {hunchback-maternal gene} {knirps gene} {Kruppel gene} can code zinc-finger transcription factors that make bands along embryo and body regions by working with maternal-effect genes and by repressing each other. Gap genes also regulate genes expressed later. Transcription-factor binding sites are high-affinity or low-affinity, so transcription-factor concentration affects which genes transcribe and how much, leading to gradients and bands. In small regions, same chemicals cause different effects.
After gap-gene expression, genes {segmentation gene} can code for transcription factors that segment body, pair segments, and make segment polarity. Segmentation genes work with gap-gene products, and interact with each other using autofeedback, to sharpen segment boundaries. Segmentation genes include pair-rule genes, such as fushi tarazu gene, even-skipped gene, hairy gene, runt gene, and eve gene.
Segmentation genes {pair-rule gene} {eve gene} {even-skipped gene} {fushi tarazu gene} {hairy gene} {runt gene} can be about splitting body regions. In small regions, same chemicals cause different effects.
Genes {segment polarity gene} can be about front and back. In small regions, same chemicals can cause different effects.
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225