EUKARYOTIC GENE STRUCTURE

EUKARYOTIC GENE STRUCTURE
CENTRAL DOGMA
EXONS INTRONS
PROMOTOR & TERMINATOR SEQUENCE
ENHANCER SILENCER
UPSTREAM&DOWNSTREAM

1. EUKARYOTIC GENE STRUCTURE PRESENTED BY: MA.NITYA

2. CENTAL DOGMA

3. EXONS Expressed (Coding) sequences, transcribed and translated. An exon is the portion of a gene that codes for amino acids. A gene starts and ends with exons . 5’ to 3’. Exons include both the untranslated regions and the protein-coding, translated regions. Exons vary in number , length and sequence.

4. INTRONS Intervening (non coding) sequences. They are removed by the process of splicing.

5. PROMOTOR SEQUENCES Transcriptional initiation region. Region RNA polymerase begins. located directly upstream or at the 5' end. RNA polymerase and transcription factors bind to the promoter sequence They define the direction of transcription and indicate which DNA strand will be transcribed. Core promotor Proximal promotor Distal promotor .

6. TERMINATOR SEQUENCE   to define the end of a transcriptional unit (such as a gene) and initiate the process of releasing the newly synthesized RNA from the transcription machinery

7. ENHANCER * enhance the transcription of an associated gene. When bound to transcriptional factors. *enhancer sequences can be positioned in both forward or reversed sequence orientations  .

8. SILENCER DNA sequence capable of binding transcription regulation factors, called repressors.  silencers prevent genes from being expressed as proteins.

9. UPSTREAM 5’UTR serve several functions including mRNA transport and initiation of translation. Signal for addition of cap. DOWNSTREAM 3’UTR serves to add mRNA stability and attachment site for poly a tail. Translation termination codon .