Aim： To identify a novel alternative transcript of the novel retinal pigment epithelial cell gene （NORPEG） expressed in the human testis. Methods： A human testis cDNA microarray was established and hybridized with...Aim： To identify a novel alternative transcript of the novel retinal pigment epithelial cell gene （NORPEG） expressed in the human testis. Methods： A human testis cDNA microarray was established and hybridized with cDNA probes from human fetal testes, adult testes and human spermatozoa. Differentially expressed clones were sequenced and analyzed. One of these clones was a short transcript of NORPEG which we proceeded to analyze by RT-PCR. Results： The novel short alternative transcript of NORPEG was isolated and named sNORPEG. It was 3486 bp in length and contained a 2952-bp open reading frame, encoding a 110.4-kDa protein of 983 amino acids. Amino acid sequence analysis showed that the sNORPEG protein contains six ankyrin repeats and two coiled-coil domains. It shares a high homology with the NORPEG and ankycorbin proteins in both its sequence and motifs. Blasting the human genome database localized sNORPEG to human chromosome 5pl 3.2-13.3. Expression profiles showed that sNORPEG was expressed in human fetal testes, adult testes and spermatozoa. Moreover, sNORPEG was found to be ubiquitously expressed in human tissues. Conclusion： sNORPEG is expressed in different developmental stages of the testis and encodes a protein that may have roles in human testis development and spermatogenesis. （Asian J Androl 2005 Sep; 7： 277-288）展开更多
Cellular homeostasis relies on components of protein quality control including chaperones and proteases. In bacteria and eukaryotic organelles, Lon proteases play a critical role in removing irreparably damaged protei...Cellular homeostasis relies on components of protein quality control including chaperones and proteases. In bacteria and eukaryotic organelles, Lon proteases play a critical role in removing irreparably damaged proteins and thereby preventing the accumulation of deleterious degradation-resistant aggregates. Gene expression, live-cell imaging, immunobiochemical, and functional complementation approaches provide conclusive evidence for Lonl dual-targeting to chloroplasts and mitochondria. Dual-organellar deposition of Lonl isoforms depends on both transcriptional regula- tion and alternative translation initiation via leaky ribosome scanning from the first AUG sequence context that deviates extensively from the optimum Kozak consensus. Organelle-specific Lonl targeting results in partial complementation of Arabidopsis Ion1-1 mutants, whereas full complementation is solely accomplished by dual-organellar targeting. Both the optimal and non-optimal AUG sequence contexts are functional in yeast and facilitate leaky ribosome scanning com- plementing the piml phenotype when the mitochondrial presequence is used. Bioinformatic search identified a limited number of Arabidopsis genes with Lonl-type dual-targeting sequence organization. Lon4, the paralog of Lonl, has an ambiguous presequence likely evolved from the twin presequences of an ancestral Lonl-like gene, generating a single dual-targeted protein isoform. We postulate that Lonl and its subfunctional paralog Lon4 evolved complementary sub- sets of transcriptional and posttranscriptional regulatory components responsive to environmental cues for dual-organel- lar targeting.展开更多
文摘Aim： To identify a novel alternative transcript of the novel retinal pigment epithelial cell gene （NORPEG） expressed in the human testis. Methods： A human testis cDNA microarray was established and hybridized with cDNA probes from human fetal testes, adult testes and human spermatozoa. Differentially expressed clones were sequenced and analyzed. One of these clones was a short transcript of NORPEG which we proceeded to analyze by RT-PCR. Results： The novel short alternative transcript of NORPEG was isolated and named sNORPEG. It was 3486 bp in length and contained a 2952-bp open reading frame, encoding a 110.4-kDa protein of 983 amino acids. Amino acid sequence analysis showed that the sNORPEG protein contains six ankyrin repeats and two coiled-coil domains. It shares a high homology with the NORPEG and ankycorbin proteins in both its sequence and motifs. Blasting the human genome database localized sNORPEG to human chromosome 5pl 3.2-13.3. Expression profiles showed that sNORPEG was expressed in human fetal testes, adult testes and spermatozoa. Moreover, sNORPEG was found to be ubiquitously expressed in human tissues. Conclusion： sNORPEG is expressed in different developmental stages of the testis and encodes a protein that may have roles in human testis development and spermatogenesis. （Asian J Androl 2005 Sep; 7： 277-288）
文摘Cellular homeostasis relies on components of protein quality control including chaperones and proteases. In bacteria and eukaryotic organelles, Lon proteases play a critical role in removing irreparably damaged proteins and thereby preventing the accumulation of deleterious degradation-resistant aggregates. Gene expression, live-cell imaging, immunobiochemical, and functional complementation approaches provide conclusive evidence for Lonl dual-targeting to chloroplasts and mitochondria. Dual-organellar deposition of Lonl isoforms depends on both transcriptional regula- tion and alternative translation initiation via leaky ribosome scanning from the first AUG sequence context that deviates extensively from the optimum Kozak consensus. Organelle-specific Lonl targeting results in partial complementation of Arabidopsis Ion1-1 mutants, whereas full complementation is solely accomplished by dual-organellar targeting. Both the optimal and non-optimal AUG sequence contexts are functional in yeast and facilitate leaky ribosome scanning com- plementing the piml phenotype when the mitochondrial presequence is used. Bioinformatic search identified a limited number of Arabidopsis genes with Lonl-type dual-targeting sequence organization. Lon4, the paralog of Lonl, has an ambiguous presequence likely evolved from the twin presequences of an ancestral Lonl-like gene, generating a single dual-targeted protein isoform. We postulate that Lonl and its subfunctional paralog Lon4 evolved complementary sub- sets of transcriptional and posttranscriptional regulatory components responsive to environmental cues for dual-organel- lar targeting.
