LINES- (long interspersed nuclear element ) Autonomous transposons these are foreign sequences that has been inserted into the chromosome. Comprises 21% of the human genome.These L1 elements are DNA sequences that range in length from a few hundred to as many as 9,000 base pairs.
SINEs- ( short interspersed nuclear element )Non -autonomous
DNA sequences (100–400 base pairs) that represent reverse-transcribed RNA molecules originally transcribed by RNA polymerase III.The most abundant SINEs are the Alu elements. There are over one million copies in the human genome (representing 9% of our total DNA).
Alu elements consist of a sequence averaging 260 base pairs that contains a site that is recognized by the restriction enzyme AluI.
Thank you for visiting my blog.Please feel free to share your comment on this article ,Please subscribe and share the articles to get more such articles.
- The functional L1 elements are about 6,500 bp in length and encode three proteins, including
- an endonuclease that cuts DNA and a
- reverse transcriptase that makes a DNA copy of an RNA transcript.
- Active L1 element is about 6kb long and consists of 2 ORFs ( ORF1 &ORF2), 5' UTR ( untranslated region) ,3' UTR contains poly A signal.
- ORF1 binds to L1 m-RNA , ORF2 contains reverse transcription activity and endonuclease domain .
5'UTR---------------O---------------------------------3' AAAAAAA ( m-RNA )
ORF1 ORF2
DNA sequences (100–400 base pairs) that represent reverse-transcribed RNA molecules originally transcribed by RNA polymerase III.The most abundant SINEs are the Alu elements. There are over one million copies in the human genome (representing 9% of our total DNA).
Alu elements consist of a sequence averaging 260 base pairs that contains a site that is recognized by the restriction enzyme AluI.
Thank you for visiting my blog.Please feel free to share your comment on this article ,Please subscribe and share the articles to get more such articles.
No comments:
Post a Comment