(19 points) You are investigating the role of long noncoding RNA (lnRNA) called
ID: 276312 • Letter: #
Question
(19 points) You are investigating the role of long noncoding RNA (lnRNA) called COOLAIRin Arabidopsiswinter annual ecotype. COOLAIR RNA is induced after an exposure to cold temperature. A mutant plant was generated by deleting the promoter region of COOLAIR. Chromatin Immunoprecipitation (ChIP) analysis was carried out on the promoter region of FLCgene to determine the relative association of each histone mark. The figure below shows the result of the ChIP analysis.
NV=no vernalization
VT0=vernalized for 40 days
VT7=vernalized for 40 days and subsequently grown for 7 days at 22?C
a.Which gene(s) mediate the change in histone mark?
b.It was found thatCOOLAIRRNA is the antisense RNA which physically associate with the FLC locus (bind to FLC gene). Further experiments also show that COOLAIRhas no RNA interference activity. Suggest the role of COOLAIRin the vernalization pathway.
HaKAme H3K4me Input No antibody HaK36H3K27me WT mutantExplanation / Answer
a. PRC (Polycomb repressive complex) genes are involved in the modification of epigenetic marks. They are HDAC, HMT, and HATs. They mediate reversible modifications of histone tails that regulate the access of RNA polymerase to promoters.
b. COOL AIR is a long noncoding RNA. It is an antisense RNA to FLC that plays an important role in chromatin regulation. FLC is a major repressor flowering in Arabidopsis. FLC levels have to be reduced in order to initiate flowering. So, COOL AIR is produced in response to signals that trigger flowering such as reproductive maturity or vernalization. COOLAIR mRNA binds to the FLC genomic locus and mediates epigenetic silencing of the FLC locus in response to vernalization. It is not involved in the post-transcriptional cleavage of the FLC transcript. It is required for coordinated switching of alternate chromatin states in response to external signals.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.