Linked Life Data

17073797

Source:http://linkedlifedata.com/resource/pubmed/id/17073797

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 6
pubmed:dateCreated
2006-10-31
pubmed:abstractText
The developmental events occurring during moulting and metamorphosis of insects are controlled by precisely timed changes in levels of ecdysteroids, the moulting hormones. The final four sequential hydroxylations of steroid precursors into the active ecdysteroid of insects, 20E (20-hydroxyecdysone), are mediated by four cytochrome P450 (P450) enzymes, encoded by genes in the Halloween family. Orthologues of the Drosophila Halloween genes phantom (phm; CYP306A1), disembodied (dib; CYP302A1), shadow (sad; CYP315A1) and shade (shd; CYP314A1) were obtained from the endocrinological model insect, the tobacco hornworm Manduca sexta. Expression of these genes was studied and compared with changes in the ecdysteroid titre that controls transition from the larval to pupal stage. phm, dib and sad, which encode P450s that mediate the final hydroxylations in the biosynthesis of ecdysone, were selectively expressed in the prothoracic gland, the primary source of ecdysone during larval and pupal development. Changes in their expression correlate with the haemolymph ecdysteroid titre during the fifth (final) larval instar. Shd, the 20-hydroxylase, which converts ecdysone into the more active 20E, is expressed in tissues peripheral to the prothoracic glands during the fifth instar. Transcript levels of shd in the fat body and midgut closely parallel the enzyme activity measured in vitro. The results indicate that these Halloween genes are transcriptionally regulated to support the high biosynthetic activity that produces the cyclic ecdysteroid pulses triggering moulting.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0300-5127
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1256-60
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
The Halloween genes code for cytochrome P450 enzymes mediating synthesis of the insect moulting hormone.
pubmed:affiliation
Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, 4000 Roskilde, Denmark. rewitz@ruc.dk
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Review, Research Support, N.I.H., Extramural