Transcription start sites, alternative

Analysis of gene structure (few days) exon-intron structure alternative promoters alternative transcription start sites alternative splicing alternative translation start sites codon phasing neighboring genes... 

The use of alternative transcription start sites results in a different 5 exon on mRNAs corresponding to... 

Alternative transcription start sites which can induce the splicing of cryptic initial exons and alternative splicing play an important role in expanding the proteincoding capacity of the genome. In FANTOM3 about 32% (16 274) of the 51135 protein-coding sequences were reported as novel. Of these 76% (12303)... 

The absolute purity of a biological substance is hard - if at all possible - to determine. Regular and sometimes only subtle protein modifications such as glycosyla-tion, alternative disulphide bond formation, deamidation, oxidation, phosphorylation, acetylation, sulfation, sulfoxidation, y-carboxylation, and pyroglutamate formation lead to protein variants that may have more or less different characteristics. Also, truncated protein variants might be generated by the presence of cryptic or alternative start sites of transcription, by premature stop of the peptide chain... 

Another important source of variation in enzymes as well as in other proteins is alternative splicing of mRNA.33 For example, transcription of the mouse a-amylase gene in the salivary gland starts at a different site (promoter) than does transcription in the liver. 

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