TEX55

The TEX55 gene is 13,893 bp and spans from base pair 119,146,151 to 119,160,042.[6] This gene is flanked by immunoglobulin superfamily member 11 and Uroplakin1B.[5]

Conceptual translation of the TEX55 gene. This image is formed from a compilation of a number of different bioinformatics tools.

The mRNA of TEX55 is 1800 base pairs long and has three exons.[6] According to GeneCard, the TEX55 mRNA has 3 theoretical splice forms, but only the one containing all three exons have been studied and characterized.[6] The 5’ UTR of the mRNA has an RFX1 binding site, which binds to a stem-loop structure just upstream of the start codon, used to activate transcription.[7][10]

The translated protein of the TEX 55 mRNA is 536 AA, a predicted molecular weight of 60 kD, had an isoelectric point of 5.51, and is highly conserved at the C-terminus.[11] Tex55 has a slightly high amount of Glutamine and a slightly low amount of Leucine, which compared to the protein database swp23s.q.[11] Multiple sequence alignment of TEX55 and 20 mammalian orthologs show that there are 28 residues,concentrated in the C-terminus, that are conserved between all proteins.[8][12] The highly conserved residues are outlined in the conceptual translation and multiple sequence analysis. Through function-region analysis, researchers found that this protein may act as an anchoring protein of cAMP-dependent type-II PK, and might be an A-kinase anchoring proteins.[13][14]

Rendering of the TEX55 protein.[14] Motifs are color coded in the following manner. Purple: NLS, blue: EF-Hand Calcium Binding Domain 10, orange: Uroplakin 1B motif, yellow: overlap between homologous domains, red: high-confidence alpha-helix.[15]

Cartoon model of the TEX55 protein[16] Red flags indicate potential phosphorylation/O-glycosylation sites. The gray flag represents the sumoylation site of TEX55. The two homologous domains and the high-confidence alpha-helix are shown in the blue pentagon and orance hexagon, respectively.

Secondary Structure

All secondary structure prediction analysis indicate that the C-terminus of Tex 55 has a high probability of being an alpha-helix, and indicate that there is little to no amount of beta-sheets. Secondary structure analysis tools predict that the majority of the Tex 55 protein is coiled domains, and alpha-helices.

Secondary structure of the TEX55 protein.[14] The secondary structure of TEX55 is mainly alpha-helices and coiled domains.

Expression of TEX55 mRNA can be found in most tissues in the human body, from the brain to the prostate.[5] However, the protein produced by this mRNA has been shown to be produced mainly in the testis of mammals, according to NCBI.[5] Analysis done by the Human Protein Atlas indicates that the TEX55 protein can be found not only in the testis, but also the bronchus, Fallopian tubes, and endometrium.[23]

Being produced mainly in the testis of mammals, researchers believe that the protein product of TEX55 plays a role in spermatogenesis.[13] It has been shown that individuals with Cryptorchidism and Sertoli-cell-only syndrome, which are both associated with sterility, do not produce this protein in their testis.[13] Microarray analysis of individuals with Teratozoospermia, a condition that is characterized by ~96% of sperm morphology being altered, indicates that TEX55 expression is reduced by ~20%.[21][24] In clinical research, the TEX55 protein products have been detected in mice starting at 38 days old, then up regulated for at least 6 month.[13]

Microarray expression analysis of TEX55 in patients with Teratzoospermia.[21]