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Objective: To examine the expression profiles of the proteins translated from Acpin1 mRNA in germ cells. Methods: Northern and western blotting of various tissues and immunohistochemical analysis of germ cells were carried out in a mouse model. Results: ACPIN1 protein was transcribed from the longer, 3′ open reading frame (ORF) of Acpin1. An alternative-splicing variant, Acpin1vs, contained only the smaller, 5′ ORF of the full-length Acpin1 gene. Its gene product, SAGSIN1, was expressed specifically in salivary glands. Retrotransposed regions of Acpin1 homology were also detected in various chromosomes, and intronless paralogous genes on the X chromosome were expressed in the testis and other tissues. The genomic structure of Acpin1 is highly conserved in mammals. Conclusion: The two ORFs on the Acpin1 mRNA are independently translated in differentiated cells. Analysis of gene Acpin1 might clarify the molecular mechanism of spermatogenesis. [ABSTRACT FROM AUTHOR]

The comprehensive changes in testicular gene expression before and after haploid germ cell differentiation were examined using microarray analysis. Approximately 14 000 expressed sequence tag (EST) clones of Mouse FANTOM Array ver.1 were hybridized with probes generated from mRNA of adult and juvenile (17 days postpartum) testes before the onset of spermiogenesis. Of 1315 genes that exhibited reproducible changes in expression ( p < 0.05), 46% exhibited an increase of twofold or more in adults compared to juveniles, and 22% a decrease of twofold or more. The analysis not only confirmed the reported haploid-specific expression of several known genes, but also provided new information on the differential expression of various other genes, including upregulated genes such as Allc and Skd3 and downregulated genes such as hbb b1, before or after the onset of spermiogenesis. Based on the fundamental difference in expression profiles, and molecular functions of the encoded products, the genes were classified into several groups: postmeiotically upregulated genes encoding various enzymes, structural and regulatory proteins, and chaperones, and downregulated genes encoding haemoglobins and oxidation/reduction-related proteins or the machinery associated with protein synthesis, such as ribosomal proteins. [ABSTRACT FROM AUTHOR]

Summary PIWI-interacting RNAs (piRNAs) are small non-coding RNAs essential for animal germ cell development. Despite intense investigation of post-transcriptional processing, chromatin regulators for piRNA biogenesis in mammals remain largely unexplored. Here we document that BTBD18 is a pachytene nuclear protein in mouse testes that occupies a subset of pachytene piRNA-producing loci. Ablation of Btbd18 in mice disrupts piRNA biogenesis, prevents spermiogenesis, and results in male sterility. Transcriptome profiling, chromatin accessibility, and RNA polymerase II occupancy demonstrate that BTBD18 facilitates expression of pachytene piRNA precursors by promoting transcription elongation. Thus, our study identifies BTBD18 as a specific controller for transcription activation through RNA polymerase II elongation at a subset of genomic piRNA loci. [ABSTRACT FROM AUTHOR]