Hey, this is an English text. I want you to translate it into the Tunisian dialect. Please follow these steps:
1. Translate step by step and highlight differences between Tunisian dialect and Modern Standard Arabic.
2. Highlight sections you are confident translating into the Tunisian dialect.
Translate this text into the Tunisian dialect, focusing on capturing the essence of the language nuances:

Introduction {#Sec1} ============ Mediator is an evolutionary conserved large multiprotein complex that plays critical role in relaying the regulatory signal from DNA-bound gene-specific transcription factors to the RNA polymerase II transcriptional machinery^[@CR1]--[@CR3]^. Mediator was discovered in yeast as a factor required for activator-dependent transcription of genes but now it is becoming clear that it is involved in almost every step of transcription of Class II genes, including pre-initiation complex formation, initiation of transcription or promoter clearing, transcript elongation, splicing of transcripts, gene looping and termination of transcription^[@CR4]--[@CR9]^. In metazoans, Mediator is composed of about 30 subunits arranged in four different modules viz Head, Middle, Tail and Kinase modules. It is considered that the Head, Middle and Tail modules form the core part of the complex whereas the Kinase module reversibly associates with it as and when required. The Kinase module is mainly involved in transcriptional repression by phosphorylating CTD (CTD- Carboxy-Terminal repeat Domain) heptads of RNA Pol II and some other proteins constituting the pre-initiation complex^[@CR10]--[@CR12]^. Being a gigantic complex, Mediator provides large and accommodating interface for several protein-protein interactions^[@CR13]^. Generally, some specific subunits interact with specific DNA-bound transcription factors and other specific subunits interact with RNA Pol II and its accessory factors constituting transcriptional machinery, forming a communication bridge between the two. Consistent to this, Mediator is considered to be a 'hub' to integrate the signals from different transcription regulators and pass the 'resultant' signal to the transcriptional machinery^[@CR3]^. RNA Pol II transcribes not only protein-coding genes but also the genomic regions that give rise to noncoding RNAs (ncRNAs). Role of Mediator in protein coding genes is extensively studied, but its importance in the regulation of ncRNAs is just emerging. In mouse embryonic stem cells, a stable molecular assembly formed between the Ada-Two-A-containing (ATAC) histone acetyltransferase and Mediator complex, regulates a subset of RNA pol II-transcribed unspliced ncRNA genes (mostly small nuclear RNA genes)^[@CR14]^. In Arabidopsis, a set of Mediator subunits is involved in the transcription of ncRNAs that helps in recruitment of RNA pol V, a plant-specific polymerase evolved from Pol II^[@CR15]^. In fission yeast, a triad of Med8-Med18-Med20 regulates transcription of ncRNA from centromeric region^[@CR16]^. Thus, function of Mediator in the transcription of ncRNAs is emerging and seems to be conserved in eukaryotes. MicroRNAs (miRNAs) are a family of well-studied small ncRNAs that regulate gene expression at post-transcriptional level by sequence-specific targeting of mRNAs causing translational repression or mRNA degradation^[@CR17],[@CR18]^. There is hardly any report but one in plants, on regulation of miRNA expression by Mediator complex. In Arabidopsis, Mediator has been shown to be involved in miRNA biogenesis by recruiting RNA Pol II to the promoters of miRNA genes^[@CR15]^. Although miRNA genes are also transcribed by RNA Pol II in metazoans^[@CR19]^, the direct involvement of Mediator complex in the regulation of miRNA expression in metazoans has not been shown. In this report, we show that MED1, a subunit in the Middle module of Mediator complex, is altered in upto 20% of breast cancer patients and is