How does Line1 integrate into the genome? SINE and ALU are proteolyzed by ORF1p

Question

How does Line1 integrate into the genome?                      

                                SINE and ALU are proteolyzed by ORF1p and ORF2p, which are then shuttled into the nucleus and promote recombination

                                ORF1p and ORF2p are encoded by Line1 mRNA and help shuttle the mRNA into the nucleus where ORF2p nicks the genome and reverse transcribes L1

                                ORF1p and ORF2p are encoded by Line1 mRNA and induce monocistronic microsatellite stabilization withing the genome

                                Line1 elements are duplicated during DNA replication because the cause Non homologous end joining during cell division

                                SINE and ALU are proteolyzed by ORF1p and ORF2p, which are then shuttled into the nucleus and promote recombination

                                ORF1p and ORF2p are encoded by Line1 mRNA and help shuttle the mRNA into the nucleus where ORF2p nicks the genome and reverse transcribes L1

                                ORF1p and ORF2p are encoded by Line1 mRNA and induce monocistronic microsatellite stabilization withing the genome

                                Line1 elements are duplicated during DNA replication because the cause Non homologous end joining during cell division

Explanation / Answer

How does Line1 integrate into the genome?  

ans:Line1 elements are duplicated during DNA replication because the cause Non homologous end joining during cell division

Explantion:

Long Interspersed Nuclear Elements(LINE) are a group of genetic elements that are found in large numbers in eukaryotic genomes, composing 17% of the human genome (99.9% of which is no longer capable of mobilization). Among the LINE, there are several subgroups, such as L1, L2 and L3. Human coding L1 begin with an untranslated region (UTR) that includes an RNA polymerase II promoter, two non-overlapping open reading frames (ORF1 and ORF2), and ends with another UTR.ORF1 encodes an RNA binding protein and ORF2 encodes a protein having an endonuclease (e.g. RNase H) as well as a reverse transcriptase. The reverse transcriptase has a higher specificity for the LINE RNA than other RNA, and makes a DNA copy of the RNA that can be integrated into the genome at a new site. The endonuclease encoded by non-LTR retroposons may be AP (Apurinic/Pyrimidinic) type or REL (Restriction Endonuclease Like) type. R2 group of elements have REL type endonuclease which shows site specificity in insertion.

The 5' UTR contains the promoter sequence, while the 3' UTR contains a polyadenylation signal (AATAAA) and a poly-A tail. Because LINEs (and other class I transposons, e.g. LTR retrotransposons and SINEs) move by copying themselves (instead of moving by a cut and paste like mechanism, as class II transposons do), they enlarge the genome. The human genome, for example, contains about 500,000 LINEs, which is roughly 17% of the genome. Of these, approximately 7,000 are full-length, a small subset of which are capable of retrotransposition.

Interestingly, it was recently found that specific LINE-1 retroposons in the human genome are actively transcribed and the associated LINE-1 RNAs are tightly bound to nucleosomes and essential in the establishment of local chromatin environment

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