Abstract

In an attempt to identify genes encoding thioester-containing proteins in the freshwater crayfish, Pacifastacus leniusculus, three different cDNAs were found. A phylogenetic analysis of these proteins indicates that they can be classified into two subfamilies: two alpha-2-macroglobulins (Pl-A2M1, Pl-A2M2) showing a close similarity to shrimp A2M, and one insect TEP-like protein (Pl-TEP). This is the first report of an insect TEP-like protein in a crustacean. Crayfish Pl-A2M1, Pl-A2M2 and Pl-TEP cDNAs encode proteins with 1480, 1586 or 1507 amino acids, respectively. Pl-A2M1, Pl-A2M2 and Pl-TEP have the basic domain structure and functionally important residues for each molecule, and their mRNA was detected in different parts of the body, suggesting that they may have different functions. Pl-A2M1 was mainly expressed in hemocytes and Pl-A2M2 was highly expressed in heart and nerve, while Pl-TEP was exclusively expressed in cuticular tissues such as gill and intestine. RNA interference of Pl-TEP in vivo resulted in that these animals were slightly less resistant when fed with the bacterium, Pseudomonas libanensis/gessardii. Furthermore, when TEP activity was blocked using methylamine followed by bacterial feeding, the animals were killed to a higher extent compared to a control group. Taken together, this indicates that Pl-TEP and/or Pl-A2M1, Pl-A2M2 may be important for the immune defense in crayfish intestine and function as a pattern recognition protein in crayfish cuticular tissues.

Links

Publisher Full Text

Authors

Wu C, Noonin C, Jiravanichpaisal P, Söderhäll I, Söderhäll K

Institution

Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.

Source

Insect biochemistry and molecular biology 42:2 2012 Feb pg 71-80

MeSH

Amino Acid Sequence
Animals
Arthropod Proteins
Astacoidea
Cloning, Molecular
Gastrointestinal Tract
Molecular Sequence Data
Phylogeny
RNA Interference
RNA, Messenger
Sequence Analysis, DNA
alpha-Macroglobulins

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22193393