S-adenosyl-L-methionine-dependent methyltransferase that specifically methylates the N(7) position of guanine 1575 (m7G1575) in 18S rRNA. Requires the methyltransferase adapter protein TRM112 for full rRNA methyltransferase activity. Important for biogenesis end export of the 40S ribosomal subunit independent on its methyltransferase activity. Required for efficient cleavage of the primary 35S precursor rRNA at site A2. Involved in positioning the proximal bud pole signal. guanosine(1575) in yeast 18S rRNA + S-adenosyl-L-methionine = N(7)-methylguanosine(1575) in yeast 18S rRNA + S-adenosyl-L-homocysteine Interacts with TRM112. Interacts with ECM16. Present with 1620 molecules/cell in log phase SD medium. Belongs to the class I-like SAM-binding methyltransferase superfamily. BUD23/WBSCR22 family.