RESUMO
To explore the association between single nucleotide polymorphisms (SNPs) in the promoter region of the inner centromere protein (INCENP) gene and bovine semen quality, the haplotypes in 250 Chinese Holstein bulls were detected using PCR-RFLP method in this study. Two SNPs (g.-556 G>T, rs 136823901 and g.-692 C>T, rs 211010999) and three haplotypes (CG, TT, TG) were identified in the promoter region of INCENP. The genotype frequency and allele frequency of these two SNPs as well as the correlation between different SNP haplotype combinations and bovine semen quality were then analyzed. Our results showed that fresh sperm motility of the GT genotype was significantly higher than that of the GG genotype (P<0.05) at the SNP site g.-556 G>T, while fresh and frozen-thawed sperm motilities of the haplotype combinations H1H1(CCGG), H1H3(CTGT), H2H3(TTGT) and H3H3(TTTT) were significantly higher than that of H1H2 (P<0.05). To further study the possible mechanisms by which g.-556 G>T and g.-692 C>T affect semen quality, three haplotype plasmids were respectively transfected into MLTC-1 cells. The TG haplotype demonstrated the highest luciferase activity, suggesting that g.-556 G>T and g.-692 C>T are functional mutations which could regulate INCENP gene expression by affecting promoter activity and thus affect semen quality.
Assuntos
Bovinos/genética , Proteínas Cromossômicas não Histona/genética , Regiões Promotoras Genéticas , Espermatozoides/metabolismo , Animais , Sequência de Bases , Bovinos/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Frequência do Gene , Genótipo , Haplótipos , Masculino , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único , Análise do Sêmen , Espermatozoides/químicaRESUMO
Rice black-streaked dwarf virus (RBSDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Fijivirus in the family Reoviridae. The genome of RBSDV consists of ten dsRNA segments. Although RBSDV has caused significant economic losses to rice and maize production in the past few years in China, its molecular diversity and evolution remain largely unknown. To elucidate the factor(s) underlying the evolution of RBSDV, we determined segment 8 (S8; carrying ORF8 encoding the minor core capsid protein) sequences of 101 samples and segment 10 (S10; carrying ORF10 encoding the major capsid protein) sequences of 103 samples. The results show that both ORF8 and ORF10 are under negative selection. The S8 of three isolates and S10 of two isolates are recombinants. The RBSDV population in China can be classified into three groups according to S8 sequences or into two groups according to S10 sequences, irrespective of host or geographical origin. Of the RBSDV isolates with both S8 and S10 sequences available, 17 are between-group reassortants and 30 are between-subgroup reassortants. The RBSDV subpopulations from different geographical regions and hosts show frequent gene flow within or between subpopulations. The RBSDV population from maize is in a state of expansion. In this study, no new emergent population was detected. Taken together, the results indicate that, in addition to recombination and negative selection, reassortment and gene flow are important factors that drive evolution of RBSDV in China.
Assuntos
Variação Genética , Oryza/virologia , Doenças das Plantas/virologia , Reoviridae/classificação , Reoviridae/genética , Zea mays/virologia , China , Análise por Conglomerados , Evolução Molecular , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Vírus Reordenados , Recombinação Genética , Reoviridae/isolamento & purificação , Seleção Genética , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
Southern rice black-streaked dwarf virus (SRBSDV) is a novel Fijivirus prevalent in rice in southern and central China, and northern Vietnam. Its genome has 10 segments of double-stranded RNA named S1 to S10 according to their size. An isolate of SRBSDV, JNi4, was obtained from naturally infected maize plants from Ji'ning, Shandong province, in the 2008 maize season. Segments S7 to S10 of JNi4 share nucleotide identities of 72.6%-73.1%, 72.3%-73%, 73.9%-74.5% and 77.3%-79%, respectively, with corresponding segments of Rice black-streaked dwarf virus isolates, and identities of 99.7%, 99.1%-99.7%, 98.9%-99.5%, and 98.6%-99.2% with those of SRBSDV isolates HN and GD. JNi4 forms a separate branch with GD and HN in the phylogenetic trees constructed with genomic sequences of S7 to S10. These results confirm the proposed taxonomic status of SRBSDV as a distinct species of the genus Fijivirus and indicate that JNi4 is an isolate of SRBSDV. Shandong is so far the northernmost region where SRBSDV is found in China.