Characterization of two mannose-binding protein cDNAs from rhesus monkey (Macaca mulatta): structure and evolutionary implications

Abstract

Mannose-binding proteins (MBPs), members of the collectin family, have been implicated as lectin opsonins for various viruses and bacteria. Two distinct but related MBPs, MBP-A and MBP-C, with approximately 55% identity at the amino acid level, have been previously characterized from rodents. In humans, however, only one form of MBP has been characterized. In this paper we report studies elucidating the evolution of primate MBPs. ELISA and Western blot analyses indicated that rhesus and cynomolgus monkeys have two forms of MBP in their sera, while chimpanzees have only one form, similar to humans. Two distinct MBP cDNA clones were isolated and characterized from a rhesus monkey liver cDNA library. Rhesus MBP-A is closely related to the mouse and rat MBP-A, showing 77% and 75% identity at the amino acid level, respectively. Rhesus MBP-A also has three cysteines at the N-terminus, similar to mouse and rat MBP-A and human MBP. Rhesus MBP-C shares 90% identity with the human MBP at the amino acid level and has three cysteines at the N-terminus, in contrast to two cysteine residues found in rodent MBP-C. A stretch of nine amino acids close to the N-terminus, absent in both mouse and rat MBP-A, but present in rodent MBP-C, chicken and human MBPs, is also found in the rhesus MBP-A. The phylogenetic analysis of rhesus and other mammalian MBPs, coupled with the serological data suggest that at least two distinct MBP genes existed prior to mammalian radiation and the hominoid ancestor apparently lost one of these genes or failed to express it.

Infections of People with Complement Deficiencies and Patients Who Have Undergone Splenectomy

“…Humans and New World monkeys have a single MBL gene (mbl2), while rodents have two homologous forms of MBL, which are designated MBL-A and MBL-C and are the products of mbl1 and mbl2 genes, respectively (176,245,301). Exon 1 harbors three missense single-nucleotide polymorphisms (SNPs) that result in amino acid changes in the first part of the collagenous region.…”

Mannose-binding lectin and its genetic variants

“…22,23 MBL-1 and MBL-2 have been detected in sera from the rhesus monkey, whereas in chimpanzee and in man MBL is only represented by MBL-2. 26 The protein-encoding region of MBL2 consists of four exons interrupted by three introns of 600, 1350 and 800 base pairs in size 21 (Figure 2). Exon 1 encodes the signal peptide, a cysteine-rich domain and seven copies of a repeated Glycine-Xaa-Yaa motif typical for the triple helix formation of collagen structures.…”

Localization of the Serine Protease-binding Sites in the Collagen-like Domain of Mannose-binding Protein

“…The first five Gly-X-Y triplets on the C-terminal side of the hinge (triplets 6 -10) are largely conserved in mammalian MBPs, whereas triplets further toward the C terminus are more variable (Fig. 1B) (21)(22)(23)(24)(25). In addition, the regions Nterminal to the hinge and toward the C-terminal end of the collagen-like domain both contain multiple potential sites of glycosylation on hydroxylysine residues.…”