spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online January 16, 2009
Journal of Experimental Biology 212, 401-412 (2009)
Published by The Company of Biologists 2009
doi: 10.1242/jeb.026112
This Article
Right arrow Summary Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Related articles in JEB
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dircksen, H.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Dircksen, H.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Insect ion transport peptides are derived from alternatively spliced genes and differentially expressed in the central and peripheral nervous system

Heinrich Dircksen

Department of Zoology, Stockholm University, Svante Arrhenius väg 14, 10691 Stockholm, Sweden


Figure 1
View larger version (49K):
[in this window]
[in a new window]

  		Fig. 1. Alignment of some insect ion transport peptide (ITP) and long ITP (ITPL) sequences in comparison with crustacean hyperglycaemic hormones (CHHs) of shore crab eyestalk ganglia [SGCHHs; Carcinus maenas, Carma, P14944 (Kegel et al., 1989Go); Orconectes limosus, Orcli, CAA55308 (Kegel et al., 1991Go)] and Carcinus maenas pericardial organ (PO), CarmaPOCHH (AAG29432) sequences from two crustaceans. The deduced ITP and ITPL sequences are shown for Manduca sexta (Manse, AY950500, AY950501), Bombyx mori (Bommo, AY950502, AY950503), Schistocerca gregaria (Schgr, AAB16822, AAB16823), Apis mellifera (Apime, XP001120062), Aedes aegypti (Aedae, AY950504, AY950505, AY950506), Anopheles gambiae [Anoga, XP313928 (Dai et al., 2007Go)] and Tribolium castaneum (Trica, ABN79657, ABN796578). Sequence similarities and identities are indicated with reference to the ITP/ITPL1-2 of Drosophila melanogaster [Drome, ABZ881400, ABZ881401, ABZ881402 (Dircksen et al. 2008Go)] by grey and black shading, respectively. The consensus estimate includes ITPs/ITPLs only; the colon (:) indicates that only closely related residues are found at this position. Note that at least 14 identical amino acid positions occur mostly in the first parts of the peptide sequences derived from the common exons (as indicated by a vertical blue line behind amino acids 40 or 41) in addition to the six invariable cysteines (red shaded). The latter probably give rise via disulphide bridges to three indicated intramolecular loops as so far confirmed only for a few CHHs (e.g. the ones shown here) and a synthetic SchgrITP (King et al., 1999Go).

 

Figure 2
View larger version (46K):
[in this window]
[in a new window]

  		Fig. 2. Schematic representation of highly conserved CHH/ITP gene structures containing exons arranged in tandem leading to derived alternative mRNA splice forms that encode the common (black) and the distinctive parts of long (red, green; POCHH/ITPL) and short (yellow; SGCHH/ITP) peptide isoforms (not exactly to scale). Note the occurrence of exons common to the first parts (black) in 5'-positions of the open reading frames (ORFs) within the derived mRNAs, and of the short splice form-specific ORF parts (yellow) always in the 3'-untranslated regions (UTRs) of the long splice forms. Also indicated are 5'- and 3'-UTRs (grey) and other proposed non-coding (white) regions of exons. Mature ITP peptides are indicated by magenta triangle lines. (A) Structures of the two mRNAs of short and long locust ITP/ITPL putative splice forms. Almost identical mRNAs lead to identical SchgrITP/LocmiITP in the two locust species, but SchgrIPTL and LocmiITPL differ by one amino acid (D66 to E66) (Macins et al., 1999Go; Meredith et al., 1996Go). (B) The chh gene of C. maenas has four exons leading to two identified mRNAs differentially expressed in the X-organ sinus gland system (CarmaSGCHH) or pericardial organ cells (CarmaPOCHH) (Dircksen et al., 2001Go). (C) The three exon Manse itp gene model and the derived and mature ManseITP/ITPL mRNA structures (Dai et al., 2007Go). (D) The current and revised five exon Drome itp gene model (CG13586, cf. current annotation) and the proposed and partially confirmed (blue arrowed lines) derived two long DromeITPL1,2 and one short DromeITP mRNA splice forms with putative 5'- and 3'-UTRs; intron 1 is drawn interrupted because it is much larger (14 kb) than shown here. Note that corresponding splice form-specific ORF parts of DromeITPL2 (red) and DromeITP mRNAs (yellow) are contained in the 3'-UTRs of the DromeITPL1 and DromeITPL2 mRNAs, respectively [after Dircksen et al., with permission (Dircksen et al., 2008Go)]. SP, signal peptide; CPRP/IPRP, CHH/ITP precursor-related peptide.

 

Figure 3
View larger version (46K):
[in this window]
[in a new window]

  		Fig. 3. CHH/ITP-like immunoreactive neuronal structures in the brain–retrocerebral complex and associated with the abdominal peripheral nervous system of Locusta migratoria. (A) Pars lateralis NSCs of varied staining intensity in the anterior right brain hemisphere and dendrite-like fibres in the superior lateral protocerebrum (SLP). Ped, pedunculus of the mushroom body. (B) Terminals in the neurosecretory lobe of the corpora cardiaca (CCNSL) and in the corpora allata (CA) arising from the NSCs shown in A. Note the fibres in the nervus corporis cardiaci II (NCAII) which connects the CC and CA. Ao, aorta. (C) Peripheral NSCs (arrows) intrinsic to neurohaemal areas of the distal perisympathetic organs (dPSOs) located at the crossing of the transverse and link nerves (TN, LN) usually attached to the ventral diaphragm muscles (VDMs); the structures are overlying the sixth abdominal ganglion (AG6) that also contains one pair of immunostained dorsal lateral putative interneurons (arrowheads). Horizontal 50 µm-thick vibratome sections (in A and B) and whole mount (in C) stained with antiOrcliCHH 1:2000 using the peroxidase–antiperoxidase (PAP) technique. Scale bars: 50 µm, A and B; 100 µm, C.

 

Figure 4
View larger version (23K):
[in this window]
[in a new window]

  		Fig. 4. Distribution scheme of ManseITP- and ManseITPL-expressing central and peripheral neurons of larval, pupal and adult stages of M. sexta; the larval part also applies identically to larvae of B. mori. ManseITP and ManseITPL occur together in the same pars lateralis (PL-)NSCs. Only ManseITP is in further lateral larval brain interneurons, and again only weakly expressed ManseITPL occurs in other adult brain interneurons. Anterior dorsal lateral interneurons in all VNC ganglia of all developmental stages, some median interneurons in pupal and adult AG2–AG9, and peripheral NS-L1 NSCs in TN-PVOs express ManseITPL, whereas ManseITP is restricted to brain neurons. SEG, suboesophageal ganglion; TG, thoracic ganglia; TAG, terminal abdominal ganglion. Slightly modified from Dai et al., with permission (Dai et al., 2007Go).

 

Figure 5
View larger version (37K):
[in this window]
[in a new window]

  		Fig. 5. Camera lucida drawings of identified PAP-stained ITP-immunoreactive neurons in whole mount preparations of larval (L3) CNS and adult brain of D. melanogaster. (A) Three larval ITP-immunoreactive neuron types: four pars lateralis NSCs (ipc-1; ITP-immunoreactive protocerebral neuron type), one suboesophageal interneuron (isog), and one to three abdominal (iag) efferent hindgut-innervating neurons; projections of ipc-1 NSC through nervi corporis cardiaci (NCC) to CC with one fibre entering the CA; the ring gland is shown artificially removed (asterisks) and slightly enlarged for clarity. PTG, prothoracic gland. (B) Adult brain showing the distribution of four ipc-1 NSCs, four ipc-2 putative NSCs, four ipc-3-type interneurons innervating a restricted anterior medial lateral neuropile area, and one to two median weakly ITP-immunoreactive ipc-4-type interneurons projecting via median bundle fibres (MBf) to SOG neuropiles. Me, medulla. Scale bar 50 µm. After Dircksen et al., with permission (Dircksen et al., 2008Go).

 

Figure 6
View larger version (12K):
[in this window]
[in a new window]

  		Fig. 6. Changes of CarmaCHH/ManseITP-like peptide immunoreactivity at periods before and after ecdysis in M. sexta. Estimated is the abundance of VNC preparations positively stained in transverse nerves (TNs) by immunocytochemistry (ICC, grey columns) and the haemolymph content (rhombi) compared with CHH equivalents in haemolymph samples (non-competitive ELISA with edible crab Cancer pagurus SGCHH as a standard). TN immunoreactivity is given as the average of the percentage of preparations in any ganglion showing TN staining. At a proportion of 1.0, all preparations show TN immunoreactivity. All values are represented with s.e.m.; different uppercase letters represent significant differences from other points on the curve at P<0.05; differing lowercase letters indicate significant differences from other bars at P<0.05. lfbm/afbm, liquid-/air-filled brown mandible stage; pE, post ecdysis stage. Slightly modified from Drexler et al., with permission (Drexler et al., 2007Go).

 

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?



© The Company of Biologists Ltd 2009