Human Testis-specific Pyridoxal Phosphate Aldehyde Kinase Variability Spliceosome Pkh-t Expression

Aim: To identify specifically expressed genes in adult testes, fetal testes and human spermatozoa. Methods: A human testis cDNA microarray was established. Then mRNAs of human adult testis, fetal testis and spermatozoa were purified and probes were prepared by a reverse transcription reaction with mRNA as template. The microarray was hybridized with probes of adult testes, fetal testes and spermatozoa. The nucleic sequences of differentially expressed genes were determined and homologies were searched in the databases of GenBank. Results: A novel human testis-specific gene, PKH-T was identified by hybridizing adult testis, fetal testis, and spermatozoa probes with a human testis cDNA microarray. The cDNA of PKH-T was 1,069 bp in length. The cDNA sequence of this clone was deposited in Genbank (AY303972). PKH-T was also determined as Interim GenSymbol (Unigene, HS.38041.) Protein analysis showed that PKH-T contained most PKH conserved motif. Homologous analysis showed that the 239 amino acid sequences deduced from the 719 bp open reading frame (ORF) had a homology with the human gene PKH (U89606). Expression profiles showed thatPKH-T was specifically strongly expressed in testis. Comparison of the differential expressions ofPKH and PKH-T in male testis of different developmental stages indicated that PKH-T expressed in adult testis and spermatozoa, but PKH expressed in adult testis, fetal testis, and aged testis. RT-PCR result indicated that PKH-T had no expression in patient testis of SCOS and partly spermatogenic arrest. Conclusion: PKH-T is a gene highly expressed in adult testis and spermatozoa. It may play an important role in spermatogenesis in humans and may be related with male infertility.