Disease relevance of msp-63

• Major sperm protein genes from Onchocerca volvulus [1].

High impact information on msp-63

• We show that the major sperm cytoskeletal protein (MSP) is a bipartite signal for oocyte maturation and sheath contraction [2].
• The Caenorhabditis elegans major sperm protein (MSP) signals oocytes, which are arrested in meiotic prophase, to resume meiosis and ovulate [3].
• These results indicate that cell body retraction is mediated by tension in the cytoskeleton, correlated with MSP depolymerization at the base of the lamellipodium [4].
• Motility is coupled to the assembly of MSP fibers near the leading edge of the pseudopod plasma membrane [5].
• They lack an axoneme or the actin and myosins of other types of motile cells, but their pseudopods contain abundant major sperm protein (MSP), a family of 14-kD polypeptides found exclusively in male gametes [6].

Biological context of msp-63

• Cell locomotion in amoeboid nematode sperm is generated by the vectorial assembly and bundling of filaments of the major sperm protein (MSP) [7].
• One of these cDNA clones was found to contain the entire nucleotide sequence for the MSP, including part of the 5' leader and all of the 3' trailing sequence [8].
• Whole genomic blots, as well as analysis of genomic clone banks, indicate that there are between 15 and 25 copies of the MSP gene in the nematode genome [8].
• No evidence was found of methylation at various restriction sites surrounding the MSP gene family, and similarly, no correlation between methylation and expression was observed [8].
• Another member of the MSP gene family that has been cloned from genomic DNA contains the entire uninterrupted structural sequence for the MSP in addition to a 5' flanking sequence containing a promoter-like region with the classic TATA box, a sequence resembling the CAAT box, and a putative ribosome-binding sequence [8].

Anatomical context of msp-63

• The major sperm protein (MSP) of the nematode Caenorhabditis elegans is a low-molecular-weight (15,000) basic protein implicated in the pseudopodial movement of mature spermatozoa [8].
• Both spermatozoa and non-motile spermatids bud MSP vesicles, but their stability and signaling properties differ [9].
• Here, we provide evidence that MSP export occurs by the budding of novel vesicles that have both inner and outer membranes with MSP sandwiched in between [9].
• The identification of the signaling function of MSP raised the question, how do spermatozoa, which are devoid of ribosomes, ER and Golgi, release a cytoplasmic protein lacking a signal sequence [9]?
• MSP gene transcription occurs only in late primary spermatocytes [10].

Associations of msp-63 with chemical compounds

• Here, we show that MSP and VAB-1 regulate the signaling properties of two Ca2+ channels that are encoded by the NMR-1 N-methyl D-aspartate type glutamate receptor subunit and ITR-1 inositol 1,4,5-triphosphate receptor [11].
• CONCLUSIONS: Our findings show that oocyte Eph receptor and somatic cell G protein signaling pathways control meiotic diapause in C. elegans, highlighting contrasts and parallels between MSP signaling in C. elegans and luteinizing hormone signaling in mammals [12].
• To examine the structure and composition of the cytoskeleton, we stabilized the extremely labile native MSP filaments by detergent lysis of sperm in the presence of either glutaraldehyde or polyethylene glycol (PEG) [13].
• Pelleting assays indicated a critical concentration for assembly of 0.2 mM for both isoforms in 30% ethanol, but alpha-MSP formed filaments at lower solvent concentration than beta-MSP [13].
• Both contain 126 amino acids and have an acetylated N-terminal alanine, but differ at four residues so that alpha-MSP is 142 Da larger and 0.6 pH unit more basic than beta-MSP [13].

Analytical, diagnostic and therapeutic context of msp-63

• We used DNA microarray data and an in situ binding assay to identify the VAB-1 Eph receptor protein-tyrosine kinase as an MSP receptor [3].
• MSP filaments are constructed from two helical subfilaments and here we describe the structure of putative MSP subfilament helices determined by X-ray crystallography at 3.3 A resolution [7].
• Southern blot analysis also indicates that there is no rearrangement or amplification within the MSP gene family during development [8].
• A library of AD-MSP mutants was generated via mutagenic PCR and screened for clones that fail to interact with LEXA-MSP [14].
• We have used electron microscopy and image processing to show that MSP filaments are constructed from two subfilament strands which are themselves formed from a helical arrangement of subunits [15].

References