Re: what does Oligo (dT)-cellulose chromatography mean?

Hi Tyron

In living cells, there are three (main) types of RNA are found – ribosomal 
RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA). A cDNA is made 
by copying  mRNA (in your case, mRNA of enzyme cellulase) using the enzyme 
reverse transcriptase.
The nascent mRNA in eukaryotic systems are modified by adding Adenine 
(~250, poly AMPnucleotides) nucleotides at the 3’end. Poly (A) enhances 
both the lifetime and translatability of mRNA.
These Poly (A) tails are exploited in their extraction and purification.  
In chromatography, oligo dT  are attached to the cellulose matrix.  Oligo 
dT are short segments of deoxyribose Thymidine nucleotides, which could 
anneal to complementary sequences, poly (A).
When the cell extract is run through the column the mRNA with poly (A) 
tail get attached to the oligo dT bound to cellulose matrix of column and 
are eluted by either slightly changing the pH or ionic strength. 

And you get a mixture of mRNAs which were synthesized at the time, 
including the mRNA of cellulase.

I hope this answers your question.  Please feel free to ask if you have 
more questions.

Man Mohan