Human A2M peptide

Thioester-containing proteins (TEPs), characterized by a unique intrachain beta-cysteinyl-gamma-glutamyl thioester bond, form an ancient and diverse family of secreted proteins that play central roles in the innate immune, response. But the existence form and immune protection mechanism of TEP in invertebrates still remain unclear, especially in the mollusks. The fragmentation and the immune-protective effect of thioester bond in CfTEP, a previously identified thioester-containing protein in scallop Chlamys farreri, were characterized in the present study. During the early embryonic development of scallop, the mRNA transcript of CfFEP could be detected in all the stages, and its expression levels in D-larvae, veliger larvae and eye-spot larvae were significantly higher than that in eggs. The CJTEP protein was also detected in peripheral of D-larvae, veliger larvae and eye-spot larva by immunofluorescence. In the adult scallop, the MEP protein was mainly distributed in the hepatopancreas, gill, kidney, gonad,.and mantle. The expression of CfrEP mRNA in the hemocytes of adult scallop was significantly up-regulated when the scallops were stimulated by LPS, PGN or beta-glucan. Two bands (100 and 55 kDa) were detected using antiCfTEP-R1 (spanned the C-terminal portion of the thioester, A2M-comp and A2M-recep domain, 942 1472), and a single band (46 kDa) was detected by using anti-CfFEP-R2 (the N-terminal portion of the following A2M-N-2 domain, 452-496) in the serum of scallop at 12 h after LPS stimulation. When the thioester bond of CfrEP protein was inactivated by injecting methylamine, the survival rate of scallop was significantly decreased after challenged by Vibrio angulillarum. All these results suggested that MEP protein existed as fragments similar to vertebrate C3, and played central roles in the immune response against pathogen in the innate immunity of scallops. (C) 2017 Elsevier Ltd. All rights reserved.

We have cloned the mouse gene coding for alpha(2)-macro-globulin in overlapping lambda clones and have analyzed its structure. The gene contains 36 exons, coding for the 4.8-kb cDNA that we cloned previously. Including putative control elements in the 5' flanking region, the gene covers about 45 kb. A region of 3.8 kb, stretching from 835 bases upstream of the cDNA start site to exon 4, including all intervening sequences, was sequenced completely. The analysis demonstrated that the putative promoter region of the mouse A2M gene differed considerably from the known promoter sequences of the human A2M gene and of the rat acute-phase A2M gene. Comparison of the exon-intron structure of all known genes of the A2M family confirmed that the rat acute phase A2M gene is more closely related to the human gene than to the mouse A2M gene. To generate mice with the A2M gene inactivated, an insertion type of construct containing 7.5 kb of genomic DNA of the mouse strain 129/J, encompassing exons 16 to 19, was synthesized. A hygromycin marker gene was embedded in intron 17. After electroporation, 198 hygromycin-resistant ES cell lines were isolated and analyzed by Southern blotting. Five ES cell lines were obtained with one allele of the mouse A2M gene targeted by this insertion construct, demonstrating that the position and the characteristics of the vector served the intended goal. (C) 1994 Academic Press, Inc.