Realizing that transcription units of human genes are often extremely long, researchers have focused on locating the beginning of genes by looking for sequences commonly found to precede transcription units. What are these sequences and how are they related to transcriptional properties of a gene? The Search for Transcription Start Sites: Uncovering the Sequences that Precede Human Gene Transcription Units

The Search for Transcription Start Sites: Uncovering the Sequences that Precede Human Gene Transcription Units

The transcription start site (TSS) of a human gene is the point at which the gene’s transcription begins. This is an important point of regulation for many genes, as the amount of transcription from the gene depends on the location of the TSS. In recent years, researchers have begun to focus on identifying the sequences that commonly precede human gene transcription units, as the transcription units are often very long. These sequences, known as promoters, are regulatory elements that are responsible for the initiation of transcription. Promoters are typically located upstream of the TSS, and they contain DNA segments called transcription factor-binding sites that bind to transcription factors (TFs). TFs are proteins that bind to these sites and recruit the RNA polymerase enzyme that begins the transcription of the gene. These sites also contain other regulatory elements that affect the amount of transcription from the gene, such as enhancers and silencers.
In a study by Kano et al. (2020), the authors used next-generation sequencing (NGS) data to investigate the properties of human promoters. The authors found that promoters typically contain a core sequence of bases, with a high frequency of specific dinucleotides and an overall higher AT content. Furthermore, the authors identified several cis-regulatory elements that are frequently associated with promoters, such as TF-binding sites and enhancers. Cont…