Predicted to enable mRNA guanylyltransferase activity and triphosphatase activity. Predicted to be involved in 7-methylguanosine mRNA capping. Predicted to act upstream of or within mRNA processing. Predicted to be located in nucleus. Is expressed in several structures, including heart; liver; lung; metanephros; and spleen. Orthologous to human RNGTT (RNA guanylyltransferase and 5'-phosphatase). [provided by Alliance of Genome Resources, Apr 2022]