MicroRNAs （miRNAs） are endogenous 22-nt RNAs, which play important regulatory roles by post-transcriptional gene silencing. A computational strategy has been developed for the identification of conserved miRNAs base...MicroRNAs （miRNAs） are endogenous 22-nt RNAs, which play important regulatory roles by post-transcriptional gene silencing. A computational strategy has been developed for the identification of conserved miRNAs based on features of known metazoan miRNAs in red flour beetle （Tribolium castaneum）, which is regarded as one of the major laboratory models of arthropods. Among 118 putative miRNAs, 47% and 53% of the predicted miRNAs from the red flour beetle are harbored by known protein-coding genes （intronic） and genes located outside （intergenic miRNA）, respectively. There are 31 intronic miRNAs in the same transcriptional orientation as the host genes, which may share RNA polymerase II and spliceosomal machinery with their host genes for their biogenesis. A hypothetical feed-back model has been proposed based on the analysis of the relationship between intronic miRNAs and their host genes in the development of red flour beetle.展开更多
To investigate whether transcription of hepatitis B virus （HBV） gene occurs in human sperm, total RNA was extracted from sperm of patients with chronic HBV infection （test-I）, from donor sperm transfected with a p...To investigate whether transcription of hepatitis B virus （HBV） gene occurs in human sperm, total RNA was extracted from sperm of patients with chronic HBV infection （test-I）, from donor sperm transfected with a plasmid containing the full-length HBV genome （test-2）, and from nontransfected donor sperm （control）, used as the template for reverse transcription-polymerase chain reaction （RT-PCR）. Positive bands for HBV DNA were observed in the test groups but not in the control. Next, to identify the role of host genes in regulating viral gene transcription in sperm, total RNA was extracted from 2-cell embryos derived from hamster oocytes fertilized in vitro by HBV-transfected （test） or nontransfected （control） human sperm and successively subjected to SMART-PCR, suppression subtractive hybridization, T/A cloning, bacterial amplification, microarray hybridization, sequencing and the Basic Local Alignment Search Tool （BLAST） search to isolate differentially expressed genes. Twenty-nine sequences showing significant identity to five human gene families were identified, with chorionic somatomammotropin hormone 2 （CSH2）, eukaryotic translation initiation factor 4 gamma 2 （EIF4G2）, pterin-4 alpha-carbinolamine dehydratase 2 （PCBD2）, pregnancy-specific beta-l-glycoprotein 4 （PSG4） and titin （TTN） selected to represent target genes. Using real-time quantitative RT-PCR （qRT-PCR）, when CSH2 and PCBD2 （or EIF4G2, PSG4 and TTN） were silenced by RNA interference, transcriptional levels of HBV s and x genes significantly decreased （or increased） （P 〈 0.05）. Silencing of a control gene in sperm did not significantly change transcription of HBV s and x genes （P 〉 0.05）. This study provides the first experimental evidence that transcription of HBV genes occurs in human sperm and is regulated by host genes.展开更多
文摘MicroRNAs （miRNAs） are endogenous 22-nt RNAs, which play important regulatory roles by post-transcriptional gene silencing. A computational strategy has been developed for the identification of conserved miRNAs based on features of known metazoan miRNAs in red flour beetle （Tribolium castaneum）, which is regarded as one of the major laboratory models of arthropods. Among 118 putative miRNAs, 47% and 53% of the predicted miRNAs from the red flour beetle are harbored by known protein-coding genes （intronic） and genes located outside （intergenic miRNA）, respectively. There are 31 intronic miRNAs in the same transcriptional orientation as the host genes, which may share RNA polymerase II and spliceosomal machinery with their host genes for their biogenesis. A hypothetical feed-back model has been proposed based on the analysis of the relationship between intronic miRNAs and their host genes in the development of red flour beetle.
基金This work was supported by the National Natural Science Foundation of China （No. 30972526） and by the Applied Basic Research Programs of Sichuan Province （No. 20141Y0110）. The authors thank Prof. Stanley Lin for his assistance in revising the final draft of the manuscript and editing for English grammar and syntax.
文摘To investigate whether transcription of hepatitis B virus （HBV） gene occurs in human sperm, total RNA was extracted from sperm of patients with chronic HBV infection （test-I）, from donor sperm transfected with a plasmid containing the full-length HBV genome （test-2）, and from nontransfected donor sperm （control）, used as the template for reverse transcription-polymerase chain reaction （RT-PCR）. Positive bands for HBV DNA were observed in the test groups but not in the control. Next, to identify the role of host genes in regulating viral gene transcription in sperm, total RNA was extracted from 2-cell embryos derived from hamster oocytes fertilized in vitro by HBV-transfected （test） or nontransfected （control） human sperm and successively subjected to SMART-PCR, suppression subtractive hybridization, T/A cloning, bacterial amplification, microarray hybridization, sequencing and the Basic Local Alignment Search Tool （BLAST） search to isolate differentially expressed genes. Twenty-nine sequences showing significant identity to five human gene families were identified, with chorionic somatomammotropin hormone 2 （CSH2）, eukaryotic translation initiation factor 4 gamma 2 （EIF4G2）, pterin-4 alpha-carbinolamine dehydratase 2 （PCBD2）, pregnancy-specific beta-l-glycoprotein 4 （PSG4） and titin （TTN） selected to represent target genes. Using real-time quantitative RT-PCR （qRT-PCR）, when CSH2 and PCBD2 （or EIF4G2, PSG4 and TTN） were silenced by RNA interference, transcriptional levels of HBV s and x genes significantly decreased （or increased） （P 〈 0.05）. Silencing of a control gene in sperm did not significantly change transcription of HBV s and x genes （P 〉 0.05）. This study provides the first experimental evidence that transcription of HBV genes occurs in human sperm and is regulated by host genes.
