High impact information on SEMG2

• Rate of molecular evolution of the seminal protein gene SEMG2 correlates with levels of female promiscuity [1].
• The first intron of GP1G does contain a region with high similarity to the coding exon of a human seminal vesicle secretory protein gene, semenogelin II [2].
• Although semenogelin expression is normally restricted to males, two SCLC cell lines from female patients were also positive for semenogelin II expression [3].
• In contrast, at both SEMG1 and SEMG2 we observed several gorilla haplotypes that contain at least one premature stop codon [4].
• Between these regions, equivalent to 594 base pairs (bp) upstream of the transcription initiation site to 12 bp downstream of the stop codon in the human semenogelin II gene, the cotton-top tamarin DNA carries a truncated LINE1 repeat [5].

Biological context of SEMG2

• Here we examine the molecular evolution of the semenogelin genes (SEMG1 and SEMG2), which code for the predominant structural proteins in human semen [4].
• Furthermore, the difference in sequence similarity indicates that the semenogelin II gene was deleted from the genome of a progenitor to the cotton-top tamarin after the duplication that yielded the two semenogelin genes seen in man [6].
• The occurrence of a second, larger form of semenogelin II was due to asparagine-linked glycosylation [7].
• We have now determined the nucleotide sequence of DNA located 5--13 kilobases (kb) downstream of the tamarin semenogelin I gene---a region that in man is occupied by the semenogelin II gene [5].

Anatomical context of SEMG2

• The primary source of these proteins is the seminal vesicles and, apart from a small production of SgII in epididymis, they have not been detected in other tissues [8].
• By immunohistochemistry, the basal cell layer of the secretory epithelium in prostate, trachea and bronchi was stained by antibodies recognizing both SgI and SgII [8].
• Transcripts in the gastro-intestinal tract and skeletal muscle almost exclusively encoded SgI, whereas in kidney and testis, SgII transcripts were predominant [8].
• Immunohistochemical double labeling with anti-CD68 antibodies revealed expression of SGII in CD68 negative, fibroblast-like cells, whereas CD68 positive macrophages did not [9].

Associations of SEMG2 with chemical compounds

• Secreted rhesus monkey semenogelin II consists of 683 amino acid residues, has a calculated M(r) of 77362, is devoid of Cys and Met, and displays a highly repetitive structure composed of ten 60-amino-acid repeats [10].

Other interactions of SEMG2

• Characterization of semenogelin II and its molecular interaction with prostate-specific antigen and protein C inhibitor [11].
• Semenogelin I and semenogelin II, the major gel-forming proteins in human semen, are substrates for transglutaminase [12].

Analytical, diagnostic and therapeutic context of SEMG2

• Southern blotting indicates that the common marmoset has genes for both SgI and SgII [13].
• In this report, we have re-examined the distribution of SgI and SgII transcripts and protein by RT-PCR and immunohistochemistry [8].
• Expression of semenogelins was previously thought to be highly specific to seminal vesicles, but Western blot analysis demonstrated that semenogelin II is widely expressed in SCLC cell lines and occasionally in other malignant cell lines [3].
• RESULTS: A 524 bp SGII-specific fragment could be amplified by PCR from the cDNA of all specimens [9].

References