Exon splicing

Left exon Right exon Spliced exon.s... 

In addition to affecting the efficiency of promoter utilization, eukaryotic cells employ alternative RNA processing to control gene expression. This can result when alternative promoters, intron-exon splice sites, or polyadenylation sites are used. Occasionally, heterogeneity within a cell results, but more commonly the same primary transcript is processed differendy in different tissues. A few examples of each of these types of regulation are presented below. 

Although there is a different pattern of exons spliced in the two AADC mRNAs, this apparent alternative splicing is a consequence of differences in transcription. In the non-neural mRNAthat initiates at exon LI,... 

Otterness DM, Szumlanski CL, Wood TC et al. Human thiopurine methyltransferase pharmacogenetics. Kindred with a terminal exon splice junction mutation that results in loss of activity. J Clin Invest 1998 101 1036-1044. 

Tissue-specific CYP4F3 isoforms regulated by alternate promoter usage and mutually exclusive exon splicing, which changes substrate specificity (Christmas... 

C. Splicing errors alter the critical sequence around an intron-exon splice junction. 

Detection of intron/exon splice sites Introns in eukaryotes cause discontinuation of the reading frame. If the analysis is not focused on a cDNA sequence, these introns must be spliced out and the exons joined to form the sequence that actually codes for the protein. Intron/exon splice sites can be predicted based on their common features. Most introns begin with the nucleotides GT and end with the nucleotides AG. There is a branch sequence near the downstream end of each intron involved in the splicing event. 

Greaser, M. L., Berri, M., and Warren, C. M. (2002). Species variations in cDNA sequence and exon splicing patterns in the extensible I-band region of cardiac titin Relation to passive tension. / Muscle. Res. Cell Motil. 23, 473-482. 

Le Bourdelles B, Boularand S, Boni C, Horellou P, Dumas S, Grima B, Mallet J (1988) Analysis of the 5 region of the human tyrosine hydroxylase gene combinatorial patterns of exon splicing generate multiple regulated tyrosine hydroxylase isoforms. J Neurochem 50 988-991. 

Faiibrother WG, Yeh RF, Sharp PA, Bulge CB (2002) Predictive identification of exonic splicing enhancers in human genes. Science 297 1007-1013 Fisher CW, Fisher CR, Chuang JL, Lau KS, Chuang DT et al (1993) Occurrence of a 2-bp (AT) deletion allele and a nonsense (G-to-T) mutant allele at the E2 (DBT) locus of six patients with maple syrup urine disease multiple-exon skipping as a secondary effect of the mutations. Am J Hum Genet 52 414-424... 

Kondo S, Yamcunoto N, Murakami T, Okumura M, Mayeda A et al (2004) Tra2 beta, SF2/ASF and SRp30c modulate the function of an exonic splicing enhancer in exon 10 of tau pre-mRNA. Genes Cells 9 121-130... 

Smith PJ, Zhang C, Wang J, Chew SL, Zhang MQ et al (2006) An increased specificity score matrix for the prediction of SF2/ASF-specific exonic splicing enhancers. Hum Mol Genet 15 2490-2508... 

Zhang XH, Chasin LA (2004) Computational definition of sequence motifs governing constitutive exon splicing. Genes Dev 18 1241-1250... 

The 65-aa DUF 1899 exhibits a prominent cluster of highly conserved (basic) amino acids at the amino terminus representing a coronin signature that has been previously su ested to harbor a putative actin binding site just downstream of a phosphoserine modification site." The three true WD40 domains that follow may vary in some coronin isoforms due to alternative exon splicing and two sequential pseudo domains exhibit much lower detectability by sequence... 

Exon splicing patterns incorporated into Figure 3 confirm their conservation in species representatives of the individual subfamUies, but marked differences and similarities between subfamihes testify to their relatedness. Only two DUF1900 sphee sites are universally conserved. 

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