Absolute mRNA levels and transcriptional regulation of the mouse testis-specific thioredoxins

Nme8 is essential for protection against chemotherapy drug cisplatin-induced male reproductive toxicity in mice

Cisplatin (CP), a chemotherapy drug commonly used in cancers treatment, causes serious reproductive toxicity. With younger cancer patients and increasing survival rates, it is important to preserve their reproductive capacity. NME8 is highly expressed in testis and contains thioredoxin and NDPK domains, suggesting it may be a target against the CP-induced reproductive toxicity. We deleted exons 6-7 of the Nme8 in mice based on human mutation sites and observed impaired transcript splicing. In mice, Nme8 was not essential for spermatogenesis, possibly due to functional compensation by its paralog, Nme5. Nme8 expression was elevated and translocated to the nucleus in response to two weeks of CP treatment. Under CP treatment, Nme8 deficiency further impaired antioxidant capacity, induced lipid peroxidation and increased ROS level, and failed to activate autophagy, resulting in aggravated DNA damage in testes and sperm. Consequently, the proliferation and differentiation of spermatogonia and the meiosis of spermatocyte were almost completely halted, and sperm motility was impaired. Our research indicates that NME8 protects against CP-induced testis and sperm damage. This may provide new insights into the physiological functions of the Nme family and potential targets for preserving fertility in young male cancer patients.

Effect of Seasonal Change on Testicular Protein Expression in White Roman Geese

The purpose of this study was to investigate the change in protein expression in the testes of ganders at various breeding stages. A total of nine 3-year-old male White Roman ganders were used. The blood and testis samples were collected at the nonbreeding, sexual reactivation, and breeding stages for sex hormone analysis and proteomic analysis, respectively. The testicular weight and serum testosterone observed for ganders at the breeding stage were higher than those for ganders at nonbreeding and sexual reactivation stages (P < 0.05). There were 124 protein spots differentially expressed in the testes of ganders at various reproductive stages. A total of 107 protein spots of 74 proteins was identified through mass spectrometry. Most of the differentially expressed proteins were responsible for the molecular functions of protein binding (24%) and catalytic activity (16%). A functional pathway analysis suggested that proteins involved in steroidogenesis, metabolism, and spermatogenesis pathways changed in the White Roman geese at various reproductive stages. In conclusion, ganders at various reproductive stages exhibited different levels of testosterone and protein expression in the testes. The varied levels of the proteins might be essential and unique key factors in seasonal reproduction in ganders.

A conserved noncoding sequence can function as a spermatocyte-specific enhancer and a bidirectional promoter for a ubiquitously expressed gene and a testis-specific long noncoding RNA

Tissue-specific gene expression is tightly regulated by various elements such as promoters, enhancers, and long noncoding RNAs (lncRNAs). In the present study, we identified a conserved noncoding sequence (CNS1) as a novel enhancer for the spermatocyte-specific mouse testicular cell adhesion molecule 1 (Tcam1) gene. CNS1 was located 3.4kb upstream of the Tcam1 gene and associated with histone H3K4 mono-methylation in testicular germ cells. By the in vitro reporter gene assay, CNS1 could enhance Tcam1 promoter activity only in GC-2spd(ts) cells, which were derived from mouse spermatocytes. When we integrated the 6.9-kb 5'-flanking sequence of Tcam1 with or without a deletion of CNS1 linked to the enhanced green fluorescent protein gene into the chromatin of GC-2spd(ts) cells, CNS1 significantly enhanced Tcam1 promoter activity. These results indicate that CNS1 could function as a spermatocyte-specific enhancer. Interestingly, CNS1 also showed high bidirectional promoter activity in the reporter assay, and consistent with this, the Smarcd2 gene and lncRNA, designated lncRNA-Tcam1, were transcribed from adjacent regions of CNS1. While Smarcd2 was ubiquitously expressed, lncRNA-Tcam1 expression was restricted to testicular germ cells, although this lncRNA did not participate in Tcam1 activation. Ubiquitous Smarcd2 expression was correlated to CpG hypo-methylation of CNS1 and partially controlled by Sp1. However, for lncRNA-Tcam1 transcription, the strong association with histone acetylation and histone H3K4 tri-methylation also appeared to be required. The present data suggest that CNS1 is a spermatocyte-specific enhancer for the Tcam1 gene and a bidirectional promoter of Smarcd2 and lncRNA-Tcam1.

Integrated application of transcriptomics, proteomics, and metallomics in environmental studies

Here we report a preliminary working scheme for the integrative application of transcriptomic, proteomic, and metallomic methodologies in environmental monitoring, by using as sentinel the wildlife species Mus spretus and as reference the gene/protein sequence databases from the key model species Mus musculus. We have demonstrated that the absolute transcript expression signatures quantified by reverse transcription (RT) and real-time polymerase chain reaction (PCR) of selected key genes (e.g., those coding for biotransformation enzymes) in M. spretus is a useful and reliable novel biomonitoring end-point. The suitability of commercial M. musculus oligonucleotide arrays for genome-wide transcriptional profiling in M. spretus has been also shown. Transcriptomic studies indicate considerable gene sequence similarities between both mouse species. Based on these similarities, we have demonstrated the applicability in free-living M. spretus of high-throughput proteomic methods, based on matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry (MALDI-TOFMS) analysis of tryptic 2D electrophoresis (2-DE) spot digest and peptide matching with M. musculus database. A metallomic approach based on size exclusion chromatography inductively coupled plasma-mass spectrometry (SEC-ICP-MS) was applied to trace metal-biomolecule profiles. A preliminary integration of these three -omics has been addressed to M. musculus/M. spretus couple, two rodent species that separated 3 million years ago. The integrated application of transcriptomic and proteomic data and the bidirectional use of metallomics and proteomics for selective isolation of metal-biomolecules are covered in the working scheme MEPROTRANS-triple-OMIC reported in this study.

Alternative splicing of c-fos pre-mRNA: contribution of the rates of synthesis and degradation to the copy number of each transcript isoform and detection of a truncated c-Fos immunoreactive species

Background

Alternative splicing is a widespread mechanism of gene expression regulation. Previous analyses based on conventional RT-PCR reported the presence of an unspliced c-fos transcript in several mammalian systems. Compared to the well-defined knowledge on the alternative splicing of fosB, the physiological relevance of the unspliced c-fos transcript in regulating c-fos expression remains largely unknown. This work aimed to investigate the functional significance of the alternative splicing c-fos pre-mRNA.

Results

A set of primers was designed to demonstrate that, whereas introns 1 and 2 are regularly spliced from primary c-fos transcript, intron 3 remains unspliced in part of total transcript molecules. Here, the two species are referred to as c-fos-2 (+ intron 3) and spliced c-fos (- intron 3) transcripts. Then, we used a quantitatively rigorous approach based on real-time PCR to provide, for the first time, the actual steady-state copy numbers of the two c-fos transcripts. We tested how the mouse-organ context and mouse-gestational age, the synthesis and turnover rates of the investigated transcripts, and the serum stimulation of quiescent cells modulate their absolute-expression profiles. Intron 3 generates an in-frame premature termination codon that predicts the synthesis of a truncated c-Fos protein. This prediction was evaluated by immunoaffinity chromatography purification of c-Fos proteins.

Conclusion

We demonstrate that: (i) The c-fos-2 transcript is ubiquitously synthesized either in vivo or in vitro, in amounts that are higher or similar to those of mRNAs coding for other Fos family members, like FosB, ΔFosB, Fra-1 or Fra-2. (ii) Intron 3 confers to c-fos-2 an outstanding destabilizing effect of about 6-fold. (iii) Major determinant of c-fos-2 steady-state levels in cultured cells is its remarkably high rate of synthesis. (iv) Rapid changes in the synthesis and/or degradation rates of both c-fos transcripts in serum-stimulated cells give rise to rapid and transient changes in their relative proportions. Taken as a whole, these findings suggest a co-ordinated fine-tune of the two c-fos transcript species, supporting the notion that the alternative processing of the precursor mRNA might be physiologically relevant. Moreover, we detected a c-Fos immunoreactive species corresponding in mobility to the predicted truncated variant.

Absolute transcript expression signatures of Cyp and Gst genes in Mus spretus to detect environmental contamination

We evaluated whether quantitation of mRNA molecules of key genes is a reliable biomonitoring end-point. We examined the Mus spretus expression levels of 19 transcripts encoding different cytochrome-P450s and glutathione transferases. Mice dwelling at the Doñana Biological Reserve were compared to those from an industrial settlement (PS). Metal biomonitoring indicated that PS animals sustained a heavier pollutant burden than those from the reference site. Transcript quantitations showed the following: (i) gender-related differences in the expression of most Cyp and Gst genes; (ii) one PS female displaying much smaller/larger transcript amounts than the remaining females; (iii) the concomitant up-regulation of Cyp1a2, Cyp2a5, Cyp2e1, Cyp4a10, Gsta1, Gsta2, Gstm1, and Gstm2 mRNAs in liver of PS males; and (iv) outstanding qualitative and quantitative differences between the hepatic expression signature of PS males and that promoted by paraquat. We conclude that (i) absolute amounts of transcripts encoding biotransformation enzymes are more potent biomarkers in males than in females, and in liver than in kidney; (ii) individual quantitations prevent biased interpretations by specimens with abnormal expression levels; and (iii)transcript expression signature of PS males is consistent with exposure to a complex profile of organic pollutants, other than oxidative stressors.