Molecular identification of a bevy of serine proteinases in Manduca sexta hemolymph.
Insect Biochem Mol Biol
; 35(8): 931-43, 2005 Aug.
Article
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| MEDLINE
| ID: mdl-15944088
ABSTRACT
Extracellular serine proteinase pathways control immune and homeostatic processes in insects. Our current knowledge of their components is limited-prophenoloxidase-activating proteinases (PAPs) are among the few hemolymph proteinases (HPs) with known functions. To identify components of proteinase systems in the hemolymph of Manduca sexta, we amplified cDNAs from larval fat body or hemocytes using degenerate primers coding for two conserved regions in S1 family serine proteinases. PCR yielded fragments encoding seven known (HP1-HP4, PAP-1, PAP-2 and PAP-3) and 18 unknown (HP5-HP22) serine proteinases. We screened cDNA libraries and isolated clones for 17 of the newly discovered HPs (HP5-HP22 except for HP11) and prepared antibodies to 14 recombinant proteins (HP6, HP8-HP10, HP12, HP14-HP19, HP21 and HP22). Fourteen of the HPs contain regulatory clip domain(s) at their amino-terminus--HP1, HP2, HP6, HP8, HP13, HP17, HP18, HP21, HP22 and PAP-1 have one, whereas HP12, HP15, PAP-2 and PAP-3 have two clip domains. Multiple sequence alignment of catalytic domains in these and other arthropod serine proteinases provided useful clues for future functional analysis. Northern blot and reverse transcription PCR (RT-PCR) analyses showed increases in HP2, HP7, HP9, HP10, HP12-HP22 mRNA levels at 24h after a bacterial challenge, and immunoblot analysis confirmed elevated concentrations of HP12, HP14-HP19, HP21 and HP22 proteins in plasma in response to injected bacteria. Hemocytes express HP13 and HP18; fat body produces HP12, HP20-HP22; both tissues synthesize the other HPs. These results collectively indicate the existence of a complex serine proteinase network in M. sexta hemolymph, predicted to mediate rapid defense responses upon wounding and/or microbial infection.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Serina Endopeptidasas
/
Hemolinfa
/
Manduca
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Insect Biochem Mol Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos