title: Cyp15F1: a novel cytochrome P450 gene linked to juvenile hormone-dependent caste differention in the termite Reticulitermes flavipes.
abstract: Termites are eusocial insects that jointly utilize juvenile hormone (JH), pheromones, and other semiochemicals to regulate caste differentiation and achieve caste homeostasis. Prior EST sequencing from the symbiont-free gut transcriptome of Reticulitermes flavipes unexpectedly revealed a number of unique cytochrome P450 (Cyp) transcripts, including fragments of a Cyp15 family gene (Cyp15F1) with homology to other insect Cyp15s that participate in JH biosynthesis. The present study investigated the role of Cyp15F1 in termite caste polyphenism and specifically tested the hypothesis that it plays a role in JH-dependent caste differentiation. After assembling the full-length Cyp15F1 cDNA sequence, we (i) determined its mRNA tissue expression profile, (ii) investigated mRNA expression changes in response to JH and the caste-regulatory primer pheromones γ-cadinene (CAD) and γ-cadinenal (ALD), and (iii) used RNA interference (RNAi) in combination with caste differentiation bioassays to investigate gene function at the phenotype level. Cyp15F1 has ubiquitous whole-body expression (including gut tissue); is rapidly and sustainably induced from 3 h to 48 h by JH, CAD, and ALD; and functions at least in part by facilitating JH-dependent soldier caste differentiation. These findings provide the second example of a termite caste regulatory gene identified through the use of RNAi, and significantly build upon our understanding of termite caste homeostatic mechanisms. These results also reinforce the concept of environmental caste determination in termites by revealing how primer pheromones, as socioenvironmental factors, can directly influence Cyp15 expression and caste differentiation.
authors.affiliation: Entomology and Nematology Department, University of Florida, Gainesville, Florida, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Tarver
authors.forename: Monique R
authors.initials: MR
authors.lastname: Coy
authors.forename: Michael E
authors.initials: ME
authors.lastname: Scharf
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics*; D020049:Isoptera / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D007605:Juvenile Hormones / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010675:Pheromones; D000081223:Polycyclic Sesquiterpenes; D034622:RNA Interference; D017422:Sequence Analysis, DNA; D012717:Sesquiterpenes
chemical_list: D019476:Insect Proteins; D007605:Juvenile Hormones; D010675:Pheromones; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C054278:gamma-cadinene; D003577:Cytochrome P-450 Enzyme System; C575574:cytochrome P-450 CYP152F1, Reticulitermes flavipes