Description: Homo sapiens sperm associated antigen 1 (SPAG1), transcript variant 1, mRNA. RefSeq Summary (NM_003114): The correlation of anti-sperm antibodies with cases of unexplained infertility implicates a role for these antibodies in blocking fertilization. Improved diagnosis and treatment of immunologic infertility, as well as identification of proteins for targeted contraception, are dependent on the identification and characterization of relevant sperm antigens. The protein expressed by this gene is recognized by anti-sperm agglutinating antibodies from an infertile woman. Furthermore, immunization of female rats with the recombinant human protein reduced fertility. This protein localizes to the plasma membrane of germ cells in the testis and to the post-acrosomal plasma membrane of mature spermatozoa. Recombinant polypeptide binds GTP and exhibits GTPase activity. Thus, this protein may regulate GTP signal transduction pathways involved in spermatogenesis and fertilization. Two transcript variants of this gene encode the same protein. [provided by RefSeq, Jul 2008]. Sequence Note: The RefSeq transcript and protein were derived from genomic sequence to make the sequence consistent with the reference genome assembly. The genomic coordinates used for the transcript record were based on alignments. Transcript (Including UTRs) Position: hg19 chr8:101,170,563-101,254,132 Size: 83,570 Total Exon Count: 19 Strand: + Coding Region Position: hg19 chr8:101,174,509-101,253,250 Size: 78,742 Coding Exon Count: 18
ID:SPAG1_HUMAN DESCRIPTION: RecName: Full=Sperm-associated antigen 1; AltName: Full=HSD-3.8; AltName: Full=Infertility-related sperm protein Spag-1; FUNCTION: Plays a role in fertilization. Binds GTP and has GTPase activity. SUBCELLULAR LOCATION: Cytoplasm. TISSUE SPECIFICITY: Detected in sperm and testis, in particular in pachytene primary spermatocytes. MISCELLANEOUS: Antibodies against SPAG1 interfere with fertilization (By similarity). SIMILARITY: Contains 9 TPR repeats. SEQUENCE CAUTION: Sequence=AAH55091.1; Type=Miscellaneous discrepancy; Note=Contaminating sequence. Potential poly-A sequence;
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on Q07617
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
