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Proteins and Proteomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
A DNA transcription unit encoding for a protein contains not only the sequence that will eventually be directly translated into the protein but also regulatory sequences that direct and regulate the synthesis of that protein. The regulatory sequence before the coding sequence is called the five-prime untranslated region (5′UTR) and is also known as the upstream process. The sequence following the coding sequence is called the three prime untranslated region (3′UTR) and is also known as the downstream process. Transcription has some proofreading mechanisms, but they are less effective than the controls for copying DNA. Therefore, transcription has a lower copying fidelity than DNA replication. As in DNA replication, DNA is read from 3′—5′ during transcription. Meanwhile, the complementary RNA is created from the 5′—3′ direction. Although DNA is arranged as two antiparallel strands in a double helix, only one of the two DNA strands, called the template strand, is used for transcription. This is because RNA is only single-stranded, as opposed to double-stranded DNA. The other DNA strand is called the coding strand because its sequence is the same as the newly created RNA transcript except for the substitution of uracil for thymine. The use of only the 3′—5′ strand eliminates the need for the Okazaki fragments seen in DNA replication (Figure 3.2).
Introduction and Background
Published in Jay L. Nadeau, Introduction to Experimental Biophysics, 2017
Another important concept in translation is that of the reading frame. Since every three bases code for an amino acid, the exact position of the start point determines the frame in which the sequence is read. A single insertion or deletion will change every subsequent amino acid (Figure 1.18). The translation of mRNA does not begin at the beginning of the molecule; most mRNAs contain a 5’ untranslated region (5’ UTR). Instead, an AUG codon (which encodes the amino acid methionine) signals the start of the protein and determines the reading frame. Any additions to the protein must then be in frame with the start codon in order to be read correctly. We will return to this in more detail in Chapter 2.
Diabetic retinopathy progression associated with haplotypes of two VEGFA SNPs rs2010963 and rs699947
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Haider Ali Alnaji, Rabab Omran, Aizhar H. Hasan, Mohammed Qasim Al Nuwaini
The VEGF (VEGF) gene is located on chromosome 6 p 21.1. About 4 kb, the size of its coding region. The VEGF gene has eight exons that may be combined in different ways to produce a wide variety of mRNAs via alternative splicing. This gene’s polymorphism exceeds the 150 SNPs in exons or promoters [11]. These SNPs are primarily clustered in the VEGF gene’s promoter and 5’-UTR [12]. The 5’-UTR has many different binding sites for transcription factors, and the polymorphisms in this region cause gene expression changes [13]. This study aimed to investigate whether DR patients had an association with genotypes of two SNPs in the VEGF gene and whether a specific set of variants of these SNPs inherited together.