Regulation of gene expression by transcription factors plays a very important role is proper patterning and growth of embryo.These transcription factors bind to cis regulatory regions of gene and hence control it. Changes or mutations in these binding sites are proved to be vital for evolution of new species.For eg : Changes in the cis regulatory regions (nucleotide sequence where transcription factors ) might create new binding sites or lose binding ability of already existing sites for transcription factors.

Regulation of gene transcription (transcriptional regulation) happens to be most famous form of regulation , but in principle evolutionary changes in gene expression can occur at many other levels. These non transcriptional mechanisms of gene regulation have been called ‘alternative regulatory levels’.

Regulatory non-coding RNA :
Several classes of regulatory non-coding RNAs have been identified, including microRNAs (miRNA) and small interfering RNAs (siRNA). microRNAs are a large family of small, ~22 nucleotide long, non-coding RNAs that have independently evolved in metazoans and plants as regulators of gene expression.

Regulatory elements in untranslated regions :
In addition to regulating translation, cis-regulatory elements in 5′and 3′untranslated regions (UTRs) can modulate mRNA stability and translational efficiency. eg : orthodenticle ,contains a vertebrate-specific 140 bp cis-regulatory element in its 3′ UTR that is essential for normal polyribosome complex formation and translation.

Splicing alternatively:

Alternative splicing is a potentially powerful mechanism to increase protein diversity and appears to be
common.

Epigentic regulation:

Gene expression can also be regulated by the state of chromatin,such as transcriptionally active euchromatin and silent heterochromatin.

Image : wikipedia

Related Posts:

• No Related Posts

SHARE THIS ARTICLE