Basic Information

Symbol
SPAG1
RNA class
mRNA
Alias
Sperm Associated Antigen 1 HSD-3.8 DNAAF13 CILD28 CT140 SP75 TPIS Infertility-Related Sperm Protein Spag-1 Dynein Axonemal Assembly Factor 13 Sperm-Associated Antigen 1 FLJ32920 TPR-Containing Protein Involved In Spermatogenesis Tetratricopeptide Repeat-Containing Protein Epididymis Secretory Protein Li 268 HEL-S-268
Location (GRCh38)
8:100157906-100259278
UCSC Genome Browser Search in Marker Scope
Forensic tag(s)
Postmortem interval inference
External database
HGNC NCBI Ensembl OMIM UniProt GTEx

MANE select

Transcript ID
NM_003114.5
Sequence length
3695.0 nt
GC content
0.4073

Transcripts

ID Sequence Length GC content
NM_001374321.1 NCBI
GAGACCCUCCCUCAGCACCUGCAGUGCAGCCAGAGCCGGUGCGGCGGCC… 3756 nt 0.4137
NM_003114.5 NCBI
GUUAGUAGGCCCGAGCAGUUUGAACUGGAGCUAUGACCACCAAAGAUUA… 3695 nt 0.4073
NM_172218.3 NCBI
GAGACCCUCCCUCAGCACCUGCAGUGCAGCCAGAGCCGGUGCGGCGGCC… 3746 nt 0.4132
Summary

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]

Forensic Context

The protein marker TPIS is identified as a biomarker for post-mortem interval (PMI) estimation in bone, where its abundance decreases post-mortem [Alex et al. DOI:10.1016/j.scijus.2025.101320].