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Major sperm protein genes from Onchocerca volvulus
A L Scott1, J Dinman, D J Sussman
1Department of Immunology and Infectious Diseases, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205.
Abstract:
Nematode spermatozoa, unlike their mammalian counterparts, are nonflagellated crawling cells. The pseudopod of these cells contains the major sperm protein (MSP) which comprises more than 15% of the protein in the sperm. MSP is presumed to function as a cytoskeletal element involved in motility. An Ascaris MSP cDNA sequence was used as a probe to identify and isolate Onchocerca volvulus MSP clones from a lambda gt11 genomic library. Two clones, OVGS-1 (765 bp) and OVGS-2 (1765 bp), were characterized by restriction endonuclease mapping and sequence analysis. Both genomic clones contain MSP protein coding regions of 99 and 282 bp separated by an intervening sequence of 153 bp. The genes OVGS-1 and OVGS-2 are 95% similar in nucleotide sequence in the protein coding regions, but only 79% similar in their intron sequences. A number of potential regulatory sequences in the flanking regions and at the exon/intron junctions of the O. volvulus MSP genes are in good agreement with consensus sequences in other eukaryotic cells. The nucleotide sequence of the O. volvulus MSP genes were over 80% similar to the Ascaris MSP cDNA sequence and 79% similar to the Caenorhabditis MSP-3 cDNA. The predicted amino acid sequence of the O. volvulus MSPs were 96% similar to each other, 90-91% similar to Ascaris MSP and 81-82% similar to Caenorhabditis MSP-3. These results offer evidence that the MSP sequences have been highly conserved throughout nematode evolution but are variable in their genomic organization and the presence of introns.
Insights
Major sperm protein (MSP) genes in nematodes show high conservation across species, indicating evolutionary stability. However, their genomic organization and intron presence vary, revealing evolutionary flexibility.
Area of Science:
- * Molecular Biology
- * Parasitology
- * Evolutionary Biology
Background:
- * Nematode spermatozoa are unique, nonflagellated crawling cells.
- * Major sperm protein (MSP) is a key cytoskeletal component in nematode sperm motility.
- * MSP constitutes over 15% of sperm protein.
Purpose of the Study:
- * To identify and characterize major sperm protein (MSP) genes in Onchocerca volvulus.
- * To compare the genomic organization and sequence similarity of O. volvulus MSP genes with other nematode species.
- * To investigate the evolutionary conservation and variability of MSP genes in nematodes.
Main Methods:
- * Isolation of Onchocerca volvulus MSP clones using an Ascaris MSP cDNA probe and a lambda gt11 genomic library.
- * Characterization of genomic clones (OVGS-1 and OVGS-2) via restriction endonuclease mapping and sequence analysis.
- * Sequence comparison of O. volvulus MSP genes with Ascaris and Caenorhabditis MSP sequences.
Main Results:
- * Two O. volvulus MSP genomic clones, OVGS-1 and OVGS-2, were identified and analyzed.
- * Genes exhibit high nucleotide similarity (95%) in coding regions but lower similarity (79%) in introns.
- * O. volvulus MSP genes show over 80% nucleotide similarity to Ascaris and 79% to Caenorhabditis MSP sequences, with high predicted amino acid similarity.
Conclusions:
- * Nematode MSP sequences are highly conserved throughout evolution, suggesting functional importance.
- * Genomic organization and intron presence of MSP genes display variability among nematode species.
- * The findings provide insights into the evolutionary dynamics of essential cytoskeletal proteins in nematodes.