Identification, developmental expression, and functions of bursicon in the tobacco hawkmoth, Manduca sexta.
During posteclosion, insects undergo sequential processes of wing expansion and cuticle tanning. Bursicon, a highly conserved neurohormone implicated in regulation of these processes, was characterized recently as a heterodimeric cystine knot protein in Drosophila melanogaster. Here we report the predicted precursor sequences of bursicon subunits (Masburs and Maspburs) in the moth Manduca sexta. Distinct developmental patterns of mRNA transcript and subunit-specific protein labeling of burs and pburs as well as crustacean cardioactive peptide in neurons of the ventral nervous system were observed in pharate larval, pupal, and adult stages. A subset of bursicon neurons located in thoracic ganglia of larvae expresses ecdysis-triggering hormone (ETH) receptors, suggesting that they are direct targets of ETH. Projections of bursicon neurons within the CNS and to neurohemal secretory sites are consistent with both central signaling and circulatory hormone functions. Intrinsic cells of the corpora cardiaca contain pburs transcripts and pburs-like immunoreactivity, whereas burs transcripts and burs-like immunoreactivity were absent in these cells. Recombinant bursicon induces both wing expansion and tanning, whereas synthetic eclosion hormone induces only wing expansion.
Dai
Li
L
Department of Entomology and Cell Biology, University of California, Riverside 92521, USA.
Dewey
Elizabeth M
EM
Zitnan
Dusan
D
Luo
Ching-Wei
CW
Honegger
Hans-Willi
HW
Adams
Michael E
ME
D000595:Amino Acid Sequence; D000818:Animals; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007150:Immunohistochemistry; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007447:Invertebrate Hormones / Q000235:genetics* / Q000378:metabolism; D018402:Manduca / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008675:Metamorphosis, Biological / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D018978:Molting / Q000235:genetics* / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D018000:Receptors, Peptide / Q000378:metabolism; D016415:Sequence Alignment; D014018:Tissue Distribution; D014921:Wings, Animal / Q000254:growth & development / Q000378:metabolism
D019476:Insect Proteins; D007447:Invertebrate Hormones; D018377:Neurotransmitter Agents; D011498:Protein Precursors; D021122:Protein Subunits; D012333:RNA, Messenger; D018000:Receptors, Peptide; C002295:bursicon