Instruct: Identify the main category of Biorxiv papers based on the titles and abstracts
Query: GC content but not nucleosome positioning directly contributes to intron-splicing efficiency in Paramecium Eukaryotic genes are interrupted by introns that must be accurately spliced from mRNA precursors. With an average length of 25 nt, the >90,000 introns of Paramecium tetraurelia stand among the shortest introns reported in eukaryotes. The mechanisms specifying the correct recognition of these tiny introns remain poorly understood. Splicing can occur co-transcriptionally and it has been proposed that chromatin structure might influence splice site recognition. To investigate the roles of nucleosome positioning in intron recognition, we determined the nucleosome occupancy along the P. tetraurelia genome. We showed that P. tetraurelia displays a regular nucleosome array with a nucleosome repeat length of [~]151 bp, amongst the smallest periodicities reported. Our analysis revealed that introns are frequently associated with inter-nucleosomal DNA, pointing to an evolutionary constraint to locate introns at the AT-rich nucleosome edge sequences. Using accurate splicing efficiency data from cells depleted for the nonsense-mediated decay effectors, we showed that introns located at the edge of nucleosomes display higher splicing efficiency than those at the centre. However, multiple regression analysis indicated that the GC content, rather than nucleosome positioning, directly contributes to intron splicing efficiency. Our data reveal a complex link between GC content, nucleosome positioning and intron evolution in Paramecium.
14
The categories of this paper are: biophysics
26
The categories of this paper are: biochemistry
1
The categories of this paper are: bioinformatics
28
The categories of this paper are: communication
15
The categories of this paper are: developmental
13
The categories of this paper are: animal
10
The categories of this paper are: and
25
The categories of this paper are: bioengineering
24
The categories of this paper are: cancer
7
The categories of this paper are: ecology
3
The categories of this paper are: evolutionary
0
The categories of this paper are: genetics
30
The categories of this paper are: scientific
27
The categories of this paper are: pathology
22
The categories of this paper are: physiology
31
The categories of this paper are: paleontology