hi guys,
had a query..kaplans says introns appear as unhybridized loops on EM wen mRNA hybridizes to template strand of DNA..polyA tail is also unhybridized as it results from PTM and is not encoded in DNA..
i wanted to know what does "unhybridized"mean?does it mean not accounted/complemented for??introns r a part of the template strand rite,so y should they be unhybridized?
thanks..
the point here that we use the complemamtary DNA starnd which is complemantary to the mature mRNA ( which lacks the introns ) so we find that HYBRIDIZAtion betwenn the cDNA & between the MRNA will occur only at areas of Exons excluding the poly a tail & the introns
ok!that was really simple!thanks rftfrt..:-)GL
dear Hunk .. after I wrote that for you I felt I just made it comlicated ,, in fact it can be easier
.. now we know that DNA contains both introns & exons ..right ?
then mRNA has both also in the start but later it will get mature so it will contain only exons & the introns r spliced ..in additon the poly AAAA tail it not coded by the DNA so when we Hybridize the orginal DAN of that gene with the mature mRNA ..we will get that figure you talked about .. this is better I guess good luck to you too dear :-))
hello hunk,
the second explanation is better and correct ......................not the first one..........its simple...hybridisation means that the two strands(dna template vs. mrna) togethre r complementary n antiprallel to each other base by base..........since introns r spliced off during ptm, there is no more base sequences left for the dna introns in mrna n this causes looping of the template strand of dna at points of introns..................same goes for poly a tail in mrna.........i hope itll help