Modern Medical Laboratory Journal

Gene transcription, a pivotal process in molecular biology, is a highly regulated and intricate mechanism that enables the expression of genetic information. It commences as RNA polymerase recognizes and binds to a specific promoter region on DNA, initiating the unwinding of the DNA double helix. Subsequently, the enzyme synthesizes a complementary RNA strand using ribonucleotides along the template DNA strand. This process elongates the RNA molecule, which may undergo post-transcriptional modifications to become mature RNA, including mRNA, rRNA, and tRNA. The termination of transcription is signaled by specific sequences, leading to the release of the RNA transcript. The regulation of gene transcription plays a fundamental role in determining gene expression and, consequently, cellular functions and responses to various stimuli. This dynamic process allows for the precise control of protein production and the adaptation of cells to their environment.
The regulated transcription of genes determines cell identity and function. Recent structural studies have elucidated mechanisms that govern the regulation of transcription by RNA polymerases during the initiation and elongation phases. Microscopy studies have revealed that transcription involves the condensation of factors in the cell nucleus. A model is emerging for the transcription of protein-coding genes in which distinct transient condensates form at gene promoters and in gene bodies to concentrate the factors required for transcription initiation and elongation, respectively. The transcribing enzyme RNA polymerase II may shuttle between these condensates in a phosphorylation-dependent manner. Molecular principles are being defined that rationalize transcriptional organization and regulation, and that will guide future investigations.
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