GeneRegulation160-page12 - Activators Plants in particular...

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Gene Regulation - 12 The hormone, ecdysone, found in flies, stimulates the transcription of the genes for the production of saliva on the polytene chromosomes. Large amounts of saliva are needed to moisten the copious amounts of food the larvae consume. Albumin synthesis in bird eggs is promoted by an estrogen-protein complex that binds near the enhancer region of the albumin gene. Estrogen is only produced during the breeding season, so no albumin is synthesized when it is not needed. The activation of the molting gene in insect larvae is controlled by a hormone that activates a regulatory protein on the gene. The androgen receptor in human males is essential for testosterone to function. Environmental
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Unformatted text preview: Activators Plants in particular have responses to environmental signal activators. Many plant growth activities are activated by light, or the absence of light. Phytochrome is a light-sensitive pigment that undergoes a conformational change to trigger signal transduction pathways that affect transcription factors. Phytochrome is involved in flowering of plants, chlorophyll synthesis and etiolation (rapid elongation of cells in the absence of light. Phytochrome is also responsible for signaling anthocyanin production in leaves prior to abscission, which gives the red pigments to leaves in autumn. Chlorophyll synthesis in response to the light activation of phytochrome...
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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