Anopheles gambiae Croquemort SCRBQ2, expression profile in the mosquito and its potential interaction with the malaria parasite Plasmodium berghei

Abstract

The scavenger receptor family comprises transmembrane proteins involved in the recognition of polyanionic ligands. Several studies have established that members of this family are involved both in immunity and in developmental processes. In Drosophila melanogaster, one of the best characterized scavenger receptors is Croquemort, which participates in the recognition of apoptotic cells in the embryo. Although comparative genomic studies have revealed the presence of four orthologs of this receptor in the malaria vector Anopheles gambiae, little is known about their function. We have investigated the expression pattern of the four Croquemort orthologs during the mosquito life cycle. Croquemort transcripts SCRBQ2 and SCRBQ4 are expressed at all the developmental stages, while expression of Croquemort transcripts SCRBQ1 and SCRBQ3 is more restricted. We have also investigated the expression of the four Croquemort orthologs in the different organs of the adult female. Croquemort transcript SCRBQ2 is highly expressed in the A. gambiae female midgut. SCRBQ2 midgut gene expression was up-regulated after a non-infected or a Plasmodium berghei-infected blood meal, compared to its expression in midguts of sugar-fed females. Interestingly, knockdown of SCRBQ2 expression by dsRNA injection resulted in a 62.5% inhibition of oocyst formation, suggesting that SCRBQ2 plays a role in Plasmodium–mosquito interactions.

MicroRNA-regulation of Anopheles gambiae immunity to Plasmodium falciparum infection and midgut microbiota

“…SCRBQ2, part of a group of scavenger receptors that recognize polyanionic ligands, contains aga-miR-305 binding sites within the coding region. Expression of scavenger receptor proteins are up-regulated following P. falciparum and P. berghei infection, and SCRBQ2 acts as a Plasmodium agonist, aiding the establishment of parasite infection (Blumberg et al, 2013; Dong et al, 2006; Gonzalez-Lazaro et al, 2009). Binding sites were also predicted within the coding region of five different clip-domain serine protease (CLIP) genes.…”

Scavenger Receptor Class B, Type I, a CD36 Related Protein inMacrobrachium nipponense: Characterization, RNA Interference, and Expression Analysis with Different Dietary Lipid Sources

“…Croquemort can act both as an essential receptor for phagocytosis of apoptotic corpses [15] and as a phagocytic receptor for Gram-positive bacteria [16]. Croquemort orthologs have also been described in Anopheles gambiae [17] and Marsupenaeus japonicus [18]. MjSR-BI, the only SR-BI identified in shrimp to date, has been reported in M. japonica [19].…”

Bacteria- and IMD Pathway-Independent Immune Defenses against Plasmodium falciparum in Anopheles gambiae

“…Fibrinogen-related proteins have been implicated in the pattern recognition processes of human and rodent malaria parasites [30], and two FBN genes ( FBN34 AGAP001554, Log2 = 1.04) and a novel gene, (XM_001231172, AGAP010772, Log2  = 1.86) encoding such putative immune factors were upregulated in the aseptic midguts by parasite infection. Another upregulated gene, SCRB5 (AGAP002738, Log2 = 3.17), belongs to a class of scavenger receptors with diverse roles in pattern recognition, phagocytosis, and Plasmodium infection [31]–[33]. A non-alternatively spliced region of the AGDSCAM gene (AGAP007092, Log2 = 1.49) was also upregulated.…”