title: Citrus, a key insect eggshell protein.
abstract: Molecular aspects of chorion synthesis in insects have been studied deeply in species with meroistic ovaries. Information available in insects with panoistic ovaries is principally structural whereas molecular information in these species is scarce. This paper seeks to balance the above situation by describing a novel chorion gene, Citrus, from the cockroach Blattella germanica, a phylogenetically basal hemimetabolan insect with reproduction regulated by juvenile hormone and with panoistic ovaries. During previous work we discovered a series of novel genes which were specifically expressed during chorion formation in B. germanica. One of them, herein named Citrus, was peculiar due to its high copy number and its very transient expression. In the present paper we characterize Citrus in terms of structure and function. The most prominent structural feature is that the protein contains a motif which is repeated 33 times encompassing almost all the sequence. By using RNAi techniques we have demonstrated that Citrus is a key player in the building of the endochorion of B. germanica eggs.
authors.affiliation: Institut de Biologia Evolutiva (CSIC-UPF), Passeig Marítim de Barceloneta, 37, 08003 Barcelona, Spain. pirles@gmail.com
authors.forename: Paula
authors.initials: P
authors.lastname: Irles
authors.forename: Maria-Dolors
authors.initials: MD
authors.lastname: Piulachs
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D002823:Chorion / Q000378:metabolism* / Q000648:ultrastructure; D003058:Cockroaches / Q000235:genetics / Q000378:metabolism*; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018628:Gene Dosage; D018507:Gene Expression Regulation, Developmental; D008845:Microinjections; D008969:Molecular Sequence Data; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D010063:Ovum / Q000378:metabolism* / Q000648:ultrastructure; D010802:Phylogeny; D034622:RNA Interference; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D004527:Egg Proteins; D011994:Recombinant Proteins; C015753:chorion proteins