RESUMO
Genetic information stored in DNA is accurately copied and transferred to subsequent generations through DNA replication. This process is accomplished through the concerted actions of highly conserved DNA replication components. Epigenetic information stored in the form of histone modifications and DNA methylation, constitutes a second layer of regulatory information important for many cellular processes, such as gene expression regulation, chromatin organization, and genome stability. During DNA replication, epigenetic information must also be faithfully transmitted to subsequent generations. How this monumental task is achieved remains poorly understood. In this review, we will discuss recent advances on the role of DNA replication components in the inheritance of epigenetic marks, with a particular focus on epigenetic regulation in fission yeast. Based on these findings, we propose that specific DNA replication components function as key regulators in the replication of epigenetic information across the genome.
Assuntos
Proteínas Cdc20 , Genética , Metabolismo , Centrômero , Metabolismo , Cromatina , Metabolismo , Proteínas Cromossômicas não Histona , Metabolismo , Replicação do DNA , DNA Fúngico , Metabolismo , Epigênese Genética , Histonas , Metabolismo , Schizosaccharomyces , Genética , Metabolismo , Proteínas de Schizosaccharomyces pombe , Genética , MetabolismoRESUMO
The Neurospora crassa fmf-1 mutation exerts an unusual 'perithecium-dominant' developmental arrest; fmf-1 x fmf-1+ cross becomes arrested in perithecial development regardless of whether the mutant participates in the cross as the male or female parent. We localized fmf-1 to the LG IL genome segment between the centromere-proximal breakpoint of the chromosome segment duplication Dp(IL)39311 and the centromere. By mapping crossovers with respect to RFLP markers in this region we further localized fmf-1 to an approximately 34-kb-genome segment. Partial sequencing of this segment revealed a point mutation in the gene NCU 09387.1, a homologue of the Schizosaccharomyces pombe ste11+ regulator of sexual development. The fmf-1 mutation did not complement a NCU 09387.1 deletion mutation, and transformation with wild-type NCU 09387.1 complemented fmf-1. S. pombe Ste11 protein (Ste11p) is a transcription factor required for sexual differentiation and for the expression of genes required for mating pheromone signalling in matP and matM cells. If FMF-1 also plays a corresponding role in mating pheromone signalling in Neurospora, then protoperithecia in an fmf-1 x fmf-1+ cross would be unable to either send or receive sexual differentiation signals and thus become arrested in development.
Assuntos
Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Genoma Fúngico , Modelos Genéticos , Mutação , Neurospora crassa/genética , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
BACKGROUND & OBJECTIVES: There is a need to delimit the areas of filariasis transmission in view of the Filariasis Elimination Programme launched in India. Infection rate in vectors is an important parameter in determining transmission and it is conventionally assessed by dissection and microscopy. A PCR assay based on Ssp I repeats of Wuchereria bancrofti has shown potential in the detection of infection in vectors. The aim of the present study was to evaluate the specificity and sensitivity of this assay on W. bancrofti and its vector, Culex quinquefasciatus, prevalent in India. METHODS: The DNA from pools of C. quinquefasciatus to which W. bancrofti microfilariae (mf) were added, was extracted by lysing with 0.1 M NaOH and 0.2 per cent sodium dodecyl sulphate (SDS), followed by silica absorption in the presence of guanidinium thiocyanate. The PCR assay of the DNA samples was carried out using NV-1 and NV-2 primers and the species specific SspI band was visualized on agarose gels stained with ethidium bromide. RESULTS: The Ssp I PCR assay was found to be highly species specific, as it did not detect the DNA of a closely related filarial parasite, Brugia malayi. The assay detected as little as 0.04 pg of W. bancrarofti DNA. Minimum number of parasite detectable in pools of mosquitoes was 1 mf. A pool size of 50 mosquitoes was found to be optimum for the PCR assay. INTERPRETATION & CONCLUSION: The Ssp I PCR assay was found to be highly specific and sensitive in detecting filarial parasite in pools of mosquitoes and therefore has potential application in rapid assessment of transmission of filariasis.