Gene expression profiling was performed using the National Institute on Aging 15,000-cDNA microarray to reveal the differential expression pattern of 160 genes between meiotic pachytene spermatocytes and postmeiotic round spermatids of the mouse. Our results indicate that more genes are expressed in spermatids than in spermatocytes. Genes participating in cell cycle regulation and chromatin structure and dynamics are preferentially expressed in spermatocytes, while genes for protein turnover, signal transduction, energy metabolism, and intracellular transport are prevalent in spermatids. This suggests that a switch of functional requirement occurs when meiotic germ cells differentiate into haploid spermatids. Concordant expression patterns were obtained when quantitative real-time polymerase chain reaction was performed to verify the microarray data. Interestingly, the majority of the differentially expressed genes were underrepresented in mitotic type A spermatogonia, and they were preferentially expressed in the testis. Our results suggest that an even higher proportion of the mouse genome is devoted to male gamete development from meiosis than was previously estimated. We also provide evidence that underscores the advantage of using purified germ cells over whole testes in profiling spermatogenic gene expression to identify transcripts that demonstrate stage-specific expression patterns. gamete biology; testis; spermatogenesis; gametogenesis; developmental biology

No abstract

There is no reliable method currently available to predict malignant potential of pheochromocytoma based on conventional histology or genetic, molecular or immunohistochemical markers. Metastasis suppressor genes affect the spread of several cancers and, therefore, may provide promise as prognostic markers or therapeutic targets for malignant pheochromocytoma. We hypothesized that the downregulation of metastasis suppressor genes in malignant pheochromocytoma may play a role in malignant behavior. We applied quantitative real-time polymerase chain reaction (QRT-PCR) to 11 metastasis suppressor genes. These genes are known to be involved in the regulation of important cancerrelated cellular events, such as cell growth regulation and apoptosis (nm23-H1, TIMP-1, TIMP-2, TIMP-3, TIMP-4, TXNIP and CRSP-3), cell-cell communication (BRMS-1), invasion (CRMP-1) and cell adhesion (E-Cad and KiSS1). The study included 15 benign and 10 malignant pheochromocytomas. Six metastasis suppressor genes (nm23-H1, TIMP-4, BRMS-1, TXNIP, CRSP-3 and E-Cad) were downregulated significantly in malignant compared to benign pheochromocytoma (p < 0.05, Mann-Whitney U-test). We applied a non-linear rule using median malignant value (MMV) as a threshold to use metastasis suppressor genes to distinguish malignant from benign samples. After cross-validation, the non-linear rule produced no errors in 10 malignant samples and 3 errors in the 15 benign samples, with an overall error rate of 12%. These results suggest that downregulation of metastasis suppressor genes reflect malignant pheochromocytoma with a high degree of sensitivity. Thus, we conclude that altered function of these metastasis suppressor gene pathways may play an important role in the malignant behavior of pheochromocytoma. Published 2004 Wiley-Liss, Inc. † Key words: pheochromocytoma; metastasis; real-time PCR A total of 13-36% of patients with sporadic pheochromocytoma develop malignant disease with an overall 5-year survival rate of 50%. [1][2][3] Because there are no reliable histological criteria for malignancy, malignant pheochromocytoma can only be diagnosed by the presence of metastatic lesions at sites where chromaffin tissue is normally absent. 4 The most common sites for metastasis are lymph nodes, bones, lungs and liver. 2 Currently, there is no cure for malignant pheochromocytoma.The lack of histological criteria for malignancy has initiated many studies to find a marker for metastatic behavior of pheochromocytoma. Markers such as p53, MIB-1/Ki-67 and telomerase, alone or in combination, have been tested for their usefulness, with some showing promising results. 5-7 Staining MIB-1 was higher in approximately 50% of malignant pheochromocytomas and was negative in all benign tumors. 5,8 Boltze et al. 7 demonstrated recently that the expression of hTERT is upregulated in 100% of malignant tumors vs. 7% of benign tumors. This gene may be a promising marker to identify malignant pheochromocytoma.Recent studies have demonstrated that altered cell cycle pathways are import...

Autism spectrum disorder is a complex neurodevelopmental disorder whose pathophysiology remains elusive as a consequence of the unavailability for study of patient brain neurons; this deficit may potentially be circumvented by neural differentiation of induced pluripotent stem cells. Rare syndromes with single gene mutations and autistic symptoms have significantly advanced the molecular and cellular understanding of autism spectrum disorders, however, in aggregate they only represent a fraction of all cases of autism. In an effort to define the cellular and molecular phenotypes in human neurons of non-syndromic autism we generated induced pluripotent stem cells (iPSCs) from three male autism spectrum disorder patients who had no identifiable clinical syndromes, and their unaffected male siblings and subsequently differentiated these patient-specific stem cells into electrophysiologically active neurons. iPSC-derived neurons from these autistic patients displayed decreases in the frequency and kinetics of spontaneous excitatory postsynaptic currents relative to controls, as well as significant decreases in Na+ and inactivating K+ voltage-gated currents. Moreover, whole-genome microarray analysis of gene expression identified 161 unique genes that were significantly differentially expressed in autistic patients iPSCs-derived neurons (> two-fold, FDR < 0·05). These genes were significantly enriched for processes related to synaptic transmission, such as neuroactive ligand-receptor signaling and extracellular matrix interactions, and were enriched for genes previously associated with autism spectrum disorder. Our data demonstrate aberrant voltage-gated currents and underlying molecular changes related to synaptic function in iPSCs-derived neurons from individuals with idiopathic autism as compared to unaffected siblings controls.

No abstract

This study was the first of its kind for adrenal tissue and provides important information about the adrenal transcriptome and aberrant signaling in an inherited form of adrenocortical hyperplasia.

No abstract

Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis-or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% -60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stagespecific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwiinteracting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis. †