Conserved Non-Coding Sequence: Difference between revisions

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Conserved noncoding sequence/CNS.  Conservation of genomic sequence that does not encode for protein.  When detected, CNSs indicate that that genomic region has function related to its primary sequence. CNSs are often operationally (or methodologically) defined by the sequence alignment algorithms used for their detection and a cutoff imposed on the percent of sequence identity and length. CNSs have been extensively characterized in vertebrate and plant lineages. Vertebrate CNSs have been defined as >= 100bp long with >70% sequence identity; plant CNSs have been dfined as >=15bp long with a blast e-value <= to that of a 15/15bp exact match. However, other operational definitions will work as well using different alignment algorithms.
Conserved noncoding sequences (CNS) are regions of the genome which do not code for proteins, yet show significantly slower rates of sequence change than truly nonfunctional sequences. Current evidence suggests that many or most conserved noncoding sequences are involved in regulating the expression of neighboring genes.<ref>Freeling, M. and Subramaniam, S. (2009). [http://www.ncbi.nlm.nih.gov/pubmed/19249238 Conserved noncoding sequences (CNSs) in higher plants.] Curr. Opin. Plant Biol 12: 126-132.</ref>
 
CNS in plants tend to be much smaller than those found in animals.
 
==Examples of regulatory CNS==
===Lateral Suppressor===
Lateral Suppressor (LAS) is a tightly regulated gene expressed specifically at the adaxial boundary of newly initiating leaf primordia. In 2011 Bodo Raatz and co-workers reported that this very specific expression pattern was regulated by a 3' prime (downstream) enhancer/suppressor which induces expression of reporter genes within the usual expression domain of LAS and represses their expression in other contexts. The authors also showed the the equivalent sequence in tomato (an asterid) retains the same function and that this conserved noncoding sequence is present downstream of orthologs of LAS in both eudicots and grasses (monocots).
 
Raatz, B. et al. (2011). [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04694.x/abstract Specific expression of LATERAL SUPPRESSOR is controlled by an evolutionarily conserved 3′ enhancer.] The Plant Journal 68: 400-412.
 
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Revision as of 00:18, 15 December 2011

Conserved noncoding sequences (CNS) are regions of the genome which do not code for proteins, yet show significantly slower rates of sequence change than truly nonfunctional sequences. Current evidence suggests that many or most conserved noncoding sequences are involved in regulating the expression of neighboring genes.[1]

CNS in plants tend to be much smaller than those found in animals.

Examples of regulatory CNS

Lateral Suppressor

Lateral Suppressor (LAS) is a tightly regulated gene expressed specifically at the adaxial boundary of newly initiating leaf primordia. In 2011 Bodo Raatz and co-workers reported that this very specific expression pattern was regulated by a 3' prime (downstream) enhancer/suppressor which induces expression of reporter genes within the usual expression domain of LAS and represses their expression in other contexts. The authors also showed the the equivalent sequence in tomato (an asterid) retains the same function and that this conserved noncoding sequence is present downstream of orthologs of LAS in both eudicots and grasses (monocots).

Raatz, B. et al. (2011). Specific expression of LATERAL SUPPRESSOR is controlled by an evolutionarily conserved 3′ enhancer. The Plant Journal 68: 400-412.

  1. Freeling, M. and Subramaniam, S. (2009). Conserved noncoding sequences (CNSs) in higher plants. Curr. Opin. Plant Biol 12: 126-132.