Molecular Biology Diagnosis and Control Strategies

**133**

**Chapter 6**

**Abstract**

**1. Introduction**

programs [3, 4].

silencing process [5].

with MicroRNAs

*Samir Casseb and Karla de Melo*

consequences of patients affected by this disease.

**Keywords:** dengue, miRNA, genetics, immunology, *Flavivirus*

(miRNAs), from precursors transcribed in the nucleus [1].

proteins involved in the degradation of the target mRNA [2].

Dengue Virus and the Relationship

Dengue is an acute febrile disease caused by a virus of the genus *Flavivirus*, family Flaviviridae, endemic in tropical regions of the globe. The agent is a virus with single-stranded RNA, classified into four distinct dengue virus (DENV) serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The host's innate and adaptive immune responses play an essential role in determining the natural history of viral infections, especially in dengue. In this context, it has observed in recent years that the presence of RNA interference (RNAi) in viral infection processes is increasing, as well as immune defense. The context microRNAs (miRNAs) go for stood out, as their presence during viral infection, both in the replication of the virus and in the defense against these infections, becomes increasingly noticeable, therefore, making it increasingly necessary to better understand the role of these small RNAs within viral infection by DENV and what their consequences are in aggravating the

RNA interference (RNAi) is understood as the mechanism of gene silencing through transcription or post-transcription. Post-transcription gene silencing (PTGS) operates through translational repression induced by microRNAs

The silencing machinery by microRNAs directs mRNA to the P bodies present in the cytoplasm. They are deprived of the translation machinery and conserve

The natural functions of RNAi and their related processes appear to be the protection of the genome against invasion by mobile genetic elements, such as viruses and transposons, as well as the functioning of eukaryotic organism development

These analyses led to the identification of proteins encoded by the host involved in gene silencing. Also, they revealed that several enzymes or essential factors are common to these processes. Some components have identified to serve as initiators. In contrast, others serve as effectors, amplifiers, and transmitters for the gene

The RNAi is widely used to fight viruses, due to the exposure of their genetic material in the intracellular environment at various stages of their replication cycle [6, 7]. Due to the distinction between viral and cellular genomes, the
