Brugia spp. and Litomosoides carinii: identification of a covalently cross-linked microfilarial sheath matrix protein (shp2).
A microfilarial sheath protein gene (shp2) coding for the major constituent of the insoluble, cross-linked sheath remnant (SR) from Brugia malayi, Brugia pahangi and Litomosoides carinii has been cloned and sequenced, based on peptide partial amino-acid sequences. All three closely related single-copy shp2 genes in the two genera carry a single intron in identical position; shp2 mRNAs are post-transcriptionally modified by both cis-splicing and trans-splicing. In accordance with their extracellular destinations the encoded proteins include signal peptide sequences; molecular masses of approx. 23 kDa are hence predicted for the mature secreted polypeptides. In their structures sheath matrix proteins shp2 may be regarded as extreme cases of a modular constitution, since these proteins largely consist of two different segments of multiple sequence repetitions, PAA and QYPQAP (or QYPQ), separated by elements of unique sequence. Extreme insolubility and cross-linking are likely to originate from these repetitive sequences within shp2, and to constitute the basic properties of a microfilarial matrix largely consisting of an shp2 network.
Hirzmann
J
J
Institut für Mikrobiologie und Molekularbiologie, Justus-Liebig-Universität Giessen, Germany.
Schnaufer
A
A
Hintz
M
M
Conraths
F
F
Stirm
S
S
Zahner
H
H
Hobom
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002009:Brugia / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005370:Filarioidea / Q000235:genetics*; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009115:Muridae / Q000469:parasitology; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D012326:RNA Splicing; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D017385:Sequence Homology; D016205:Sigmodontinae / Q000469:parasitology; D012995:Solubility; D013045:Species Specificity
D018076:DNA, Complementary; D015801:Helminth Proteins; C095048:microfilarial sheath protein, Helminth