Please help me out with this:
You have just located a nucleolus in the nucleus. You are able to excise thsi area of the genome and express the genesof this chromosomal fraction in vitro (in a test tube). What genes would you most likely find expressed from this portion of the cell's DNA?
I. tRNA
II. ribonsomal
III. cyclin
IV. cyclin dependent kinase
I am leaning more toward "IV" becasue cyclin denpendent kinases exhibit enzymatic activity only when they are bound to an activator (e.i. cyclin). Do you think my choice is correct.
Read the quote below and choose the answer you think is right. Post it here and I'll check it for you.
"The main role of the nucleolus is considered to be ribosome biogenesis, since its fundamental component rDNA codes for preribosomal RNA. Briefly, during synthesis of the rRNA, nucleotide modifications are made by small nucleolar RNPs (snoRNPs), and a number of proteins become associated with the rRNA transcript. The transcript is cleaved to separate the mature rRNAs, which leave for the cytosol through nuclear pores. These nuclear pores are known as the Nuclear Pore Complex (NPC)."
source:
http://en.wikipedia.org/wiki/Nucleolus
Based on the quote you provided from Wikipedia, it is clear that the main role of the nucleolus is in ribosome biogenesis, as it contains the rDNA that codes for preribosomal RNA. Therefore, the genes most likely to be expressed from this portion of the cell's DNA would be related to ribosome biogenesis.
Out of the options given, it seems that II. ribosomal genes would be the most likely to be expressed from this portion of the DNA. This is because ribosomes are composed of ribosomal RNA (rRNA) and ribosomal proteins, and the nucleolus is involved in the formation of rRNA and the assembly of ribosomal subunits.
So, based on the information provided, it is likely that ribosomal genes would be expressed from the nucleolus.