Enables G-quadruplex RNA binding activity. Involved in regulation of RNA splicing. Acts upstream of or within learning or memory and negative regulation of gene expression. Located in nuclear speck. Is expressed in several structures, including branchial arch; heart; limb; nervous system; and sensory organ. Human ortholog(s) of this gene implicated in X-linked intellectual developmental disorder 109. Orthologous to human AFF2 (AF4/FMR2 family member 2). [provided by Alliance of Genome Resources, Apr 2022]