TY - JOUR
T1 - Biological solution conditions and flanking sequence modulate LLPS of RNA G-quadruplex structures
AU - Williams, Allison M.
AU - Dickson, Taylor M.
AU - Lagoa-Miguel, Claudia A.
AU - Bevilacqua, Philip C.
N1 - Publisher Copyright:
© 2022 Williams et al.
PY - 2022/9
Y1 - 2022/9
N2 - Guanine-rich regions of DNA or RNA can form structures with two or more consecutive G-quartets called G-quadruplexes (GQ). Recent studies reveal the potential for these structures to aggregate in vitro. Here, we report effects of in vivo concentrations of additives-amino acids, nucleotides, and crowding agents-on the structure and solution behavior of RNAs containing GQ-forming sequences. We found that cytosine nucleotides destabilize a model GQ structure at biological salt concentrations, while free amino acids and other nucleotides do not do so to a substantial degree. We also report that the tendency of folded GQs to form droplets or to aggregate depends on the nature of flanking sequence and the presence of additives. Notably, in the presence of biological amounts of polyamines, flanking regions on the 5'-end of the RNA drive more droplet-like phase separation, while flanking regions on the 3'-end, as well as both the 5'- and 3'-ends, induce more condensed, granular structures. Finally, we provide an example of a biological sequence in the presence of polyamines and show that crowders such as PEG and dextran can selectively cause its phase separation. These findings have implications for the participation of GQS in LLPS in vivo.
AB - Guanine-rich regions of DNA or RNA can form structures with two or more consecutive G-quartets called G-quadruplexes (GQ). Recent studies reveal the potential for these structures to aggregate in vitro. Here, we report effects of in vivo concentrations of additives-amino acids, nucleotides, and crowding agents-on the structure and solution behavior of RNAs containing GQ-forming sequences. We found that cytosine nucleotides destabilize a model GQ structure at biological salt concentrations, while free amino acids and other nucleotides do not do so to a substantial degree. We also report that the tendency of folded GQs to form droplets or to aggregate depends on the nature of flanking sequence and the presence of additives. Notably, in the presence of biological amounts of polyamines, flanking regions on the 5'-end of the RNA drive more droplet-like phase separation, while flanking regions on the 3'-end, as well as both the 5'- and 3'-ends, induce more condensed, granular structures. Finally, we provide an example of a biological sequence in the presence of polyamines and show that crowders such as PEG and dextran can selectively cause its phase separation. These findings have implications for the participation of GQS in LLPS in vivo.
UR - http://www.scopus.com/inward/record.url?scp=85136909424&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85136909424&partnerID=8YFLogxK
U2 - 10.1261/rna.079196.122
DO - 10.1261/rna.079196.122
M3 - Article
C2 - 35760522
AN - SCOPUS:85136909424
SN - 1355-8382
VL - 28
SP - 1197
EP - 1209
JO - RNA
JF - RNA
IS - 9
ER -