Developmentally regulated expression of a unique small heat shock protein in Brugia malayi.
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.
Raghavan
N
N
Department of Molecular Microbiology and Immunology, Johns Hopkins School of Hygiene and Public Health, Baltimore, MD 21205, USA.
Ghosh
I
I
Eisinger
W S
WS
Pastrana
D
D
Scott
A L
AL
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D017178:Brugia malayi / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response; D015801:Helminth Proteins; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; C403772:HSP-s1 protein, Brugia malayi; D006360:Heat-Shock Proteins; D015801:Helminth Proteins; D018832:Molecular Chaperones