Between B and C but not sure What is the experimental basis for concluding that
ID: 223935 • Letter: B
Question
Between B and C but not sure What is the experimental basis for concluding that puffs in polytene chromosomes and loops in lampbrush chromosomes are areas of Intense transcription of RNA? a. Electron microscopy of RNA-polymerase combined with biochemical analysis have shown a high levels of fluorescence of RNA incorporation, indicating intense transcription. b. Radioactively labeled RNA precursors followed by autoradiography have shown a high rate of RNA incorporation. Indicating intense transcription. c. Fluorescent antibodies against RNA polymerase have shown high levels of fluorescent RNA Incorporation, indicating intense transcription. d. Density analysis of RNA-polymerase has shown a high rate of RNA Incorporation, indicating Intense transcription.
Explanation / Answer
In many expreiments after the flat-embedding of chromosomes isolated at near physiological salt concentrations,which in turn is followed by ultrathin sectioning for electron microscopy, the lateral loops with numerous attached transcript fibrils could be clearly distinguished.Northern blot is also used to experimentally conclude the pertinent.
An important tool for experimental conclusion is the labeling of polytene chromosome squash preparations with antibodies to the enzymes, transcription factors, or histone modifications of interest.Transcriptional regulation in eukaryotes requires RNA polymerase II along with a variety of activators, repressors, chromatin-remodeling factors, and other chromatin-associated proteins.
Thus, option C.
References
1.Tsvetkov, A.,Jantsch,M.,Wu,Z.,Murphy,C.,& Gall,J,G.(1992).Transcription on Lampbrush Chromosome Loops in the Absence of U2 snRNA.Molecular biology of the cell,249-261.
2.Scheer,U.(1987).Structure of lampbrush chromosome loops during different states of transcriptional activity as visualized in the presence of physiological salt concentrations.Biology of the cell,33-42.
3.Johansen,K,M.,Cai,W.,Deng,H.,Bao,X.,Zhang,W.,Girton,J.,& Johansen,J.(2010).POLYTENE CHROMOSOME SQUASH METHODS FOR STUDYING TRANSCRIPTION AND EPIGENETIC CHROMATIN MODIFICATION IN DROSOPHILA USING ANTIBODIES.US National library of medicines,National institutes of health,48(4),387.
4.Schwartz,B,E.,& Ahmad,K.(2005).Transcriptional activation triggers deposition and removal of the histone variant H3.3.US National library of medicines,National institutes of health,19(7),804-814.
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