Raghavan N, Ghosh I, Eisinger WS, Pastrana D, Scott AL. Developmentally regulated expression of a unique small heat shock protein in Brugia malayi.
Mol Biochem Parasitol 1999;
104:233-46. [PMID:
10593178 DOI:
10.1016/s0166-6851(99)00150-4]
[Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A screen of an expression library from the fourth larval stage (L4) of the parasitic nematode Brugia malayi resulted in the identification of a 727 bp full-length cDNA with 29-40% identity to members of the small heat shock family of proteins (Bm-hsp-s1). The open reading frame encoded a protein of approximately 18 kDA (Bm-HSP-s1). An alignment of the Bm-HSP-s1 sequence with the sequences of small HSPs from vertebrate and invertebrate species demonstrated that a majority of the identity was concentrated in the central alpha-crystallin domain. Bm-HSP-s1 was constitutively produced by L4 and adult parasites and at low levels by third-stage larvae (L3), but not by first-stage larvae (microfilariae). In adult parasites, Bm-HSP-s1 was localized to the body wall muscle cells and to the cells of the hypodermis/lateral cord. Bm-HSP-s1 production was induced in adult and L3 incubated at 42 degrees C and in L3s during the developmental transition from vector-stage to vertebrate-stage parasites at 37 degrees C. Neither increased nor decreased temperatures induced Bm-HSP-s1 production in microfilariae. Nitric oxide induced low-level, transient Bm-HSP-s1 synthesis in adults, but not in microfilariae. Bm-HSP-s1 did not function as a molecular chaperone to prevent heat-induced aggregation of a test substrate. The developmentally regulated expression and inducable nature of Bm-HSP-s1 suggests that it may have a stage-restricted role in maintaining parasite homeostasis.
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