Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Endocrinology & Metabolism, AMINO-ACID-SEQUENCE, CORPORA CARDIACA, PROTHORACICOTROPIC HORMONE, MOLECULAR CHARACTERIZATION, RT-PCR, EXPRESSION, DROSOPHILA, MOSQUITO, GROWTH, CELLS, Amino Acid Sequence, Animals, Base Sequence, Cloning, Molecular, DNA, Complementary, Female, Grasshoppers, Insect Hormones, Insect Proteins, Insulin, Male, Molecular Sequence Data, Nerve Tissue Proteins, Organ Specificity, Peptides, 0707 Veterinary Sciences, 1103 Clinical Sciences, 1114 Paediatrics and Reproductive Medicine, 3202 Clinical sciences

Abstract:

Members of the insulin superfamily are not restricted to vertebrates, but have also been identified in invertebrate species. In the current report, we present the characterization of Scg-insulin-related peptide (IRP), an insulin-related peptide in the desert locust, Schistocerca gregaria. This peptide was isolated from corpora cardiaca (CC) extracts by means of a high-performance liquid chromatography (HPLC)-based purification strategy. Subsequent cloning and sequencing of the corresponding cDNA revealed that the encoded Scg-IRP precursor displays the structural organization that is typical for members of the insulin superfamily. Moreover, immunocytochemistry on brain tissue sections demonstrated the presence of Scg-IRP in median neurosecretory cells of the pars intercerebralis and their projections towards the storage part of the CC. Quantitative real-time RT-PCR studies revealed the presence of Scg-IRP transcripts in a variety of tissues, including nervous tissue and fat body. Furthermore, these transcripts showed a tissue- and phase-dependent, temporal regulation during the reproductive cycle of adult males and females. Finally, we demonstrated that Scg-IRP interacts in vitro with a recombinant neuroparsin, a locust protein displaying sequence similarity with vertebrate IGF binding proteins.