Which of the following is a characteristic of RNA splicing in Eukaryotes?
a. Exon/intron boundaries are typically characterized by a 5' GU splice junction and a 3' AG splice junction.
b. After splicing occurs, the U1, U2, U5, U6 snRNP complex removes remaining exons for degradation.
c. It involves removal of introns from a gene sequence followed by transcription and subsequent splicing of exons.
d. It involves recognition of sequence-specific intron/exon boundary sites by cytoplasmic proteins.

Respuesta :

Answer:

The correct answer is a. Exon/intron boundaries are typically characterized by a 5' GU splice junction and a 3' AG splice junction.

Explanation:

Splicing is the process in which the non-coding introns are removed from the mRNA and only coding sequences remains in mRNA.  

The splicing of introns depends on the recognition of splice site pair. Usually, 5'-GU-3' is 5' splice site and 5'-AG-3' is 3' splice site which makes the boundary of introns/exons and these two nucleotides are important to recognize the introns.

There are some additional conserved sequence at these two splice site which help in recognition of introns. First, a lariate structure is formed when 5'-GU-3' is cleaved and joined to the branch point that is present near 3' slice site. Then 3' splice site is cleaved which releases the intron. Therefore the correct answer is a.