plant cDNA - (Sep/25/2001 )
I have three cDNA clones for a single gene in plants. All of them have the same ORF, and differ only in that the lengths of their 3'UTR are different. Can anyone explain me why it happens? Does it mean that there are different types of mRNA from this single gene? Thanks a lot.
you need to give us some more information. How were these isolated? If the cDNA was made using oligodT primers, for instance, it is simply a matter of the reverse transcriptase making it further 5' in some of the clones. If the coding sequences of the genes are exactly the same, I doubt if you can conclude that the genes are different based on 3'UTR length differences alone. Try screening a genomic library, sequence a few clones and then you may have a better idea about the gene's structure. Or maybe try 5'RACE done on high quality mRNA.
Thanks for your reply. Two of cDNA clones (I know) were made by oligodT primers, and after I sequenced them, both of them show poly(A) sequences. So it seems that they are from differen mRNAs with different poly(A) sites. Compared with genomic sequence, all the sequences are the same except for the lengths of 3'UTR.
Oops, you said 3' not 5'. Still, if the cDNA was made with random primers, you may still get differnt lengths. The genomic sreen or 3'RACE will still help you out though