Immunogen sequence: MAVPETRPNH TIYINNLNEK IKKDELKKSL YAIFSQFGQI LDILVSRSLK MRGQAFVIFK EVSSATNALR SMQGFPFYDK PMRIQYAKTD SDIIAKMKGT. The protein encoded by this gene associates with stem loop II of the U1 small nuclear ribonucleoprotein, which binds the 5'