A common feature of many eukaryotic mRNAs is the presence of a rather long 3′ UTR, which often contains consensus sequences. Creatine kinase B (CK-B) is an important enzyme in cellular metabolism. Certain cells—termed U937D cells—have lots of CK-B mRNA, but no CK-B enzyme is present. In these cells, the 5′ end of the CK-B mRNA is bound to ribosomes, but the mRNA is apparently not translated. Something inhibits the translation of the CK-B mRNA in these cells. Researchers introduced numerous short segments of RNA containing only 3′ UTR sequences into U937D cells. As a result, the U937D cells began to synthesize the CK-B enzyme, but the total amount of CK-B mRNA did not increase. The introduction of short segments of other RNA sequences did not stimulate the synthesis of CK-B; only the 3′ UTR sequences turned on the translation of the enzyme. On the basis of these results, propose a mechanism for the inhibition of CK-B translation in the U937D cells. Explain how the introduction of short segments of RNA containing the 3′ UTR sequences might remove that inhibition.
Bacterial Genomics
The study of the morphological, physiological, and evolutionary aspects of the bacterial genome is referred to as bacterial genomics. This subdisciplinary field aids in understanding how genes are assembled into genomes. Further, bacterial or microbial genomics has helped researchers in understanding the pathogenicity of bacteria and other microbes.
Transformation Experiment in Bacteria
In the discovery of genetic material, the experiment conducted by Frederick Griffith on Streptococcus pneumonia proved to be a stepping stone.
Plasmids and Vectors
The DNA molecule that exists in a circular shape and is smaller in size which is capable of its replication is called Plasmids. In other words, it is called extra-chromosomal plasmid DNA. Vectors are the molecule which is capable of carrying genetic material which can be transferred into another cell and further carry out replication and expression. Plasmids can act as vectors.
A common feature of many eukaryotic mRNAs is the presence of a
rather long 3′ UTR, which often contains consensus sequences. Creatine
kinase B (CK-B) is an important enzyme in cellular
cells—termed U937D cells—have lots of CK-B mRNA, but no CK-B
enzyme is present. In these cells, the 5′ end of the CK-B mRNA is
bound to ribosomes, but the mRNA is apparently not translated.
Something inhibits the translation of the CK-B mRNA in these cells.
Researchers introduced numerous short segments of RNA containing
only 3′ UTR sequences into U937D cells. As a result, the U937D cells
began to synthesize the CK-B enzyme, but the total amount of CK-B
mRNA did not increase. The introduction of short segments of other
RNA sequences did not stimulate the synthesis of CK-B; only the 3′
UTR sequences turned on the translation of the enzyme.
On the basis of these results, propose a mechanism for the inhibition
of CK-B translation in the U937D cells. Explain how the introduction of
short segments of RNA containing the 3′ UTR sequences might remove
that inhibition.
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