Involved in histone 3'-end pre-mRNA processing by associating with U7 snRNP and interacting with SLBP/pre-mRNA complex. Increases histone 3'-end pre-mRNA processing but has no effect on U7 snRNP levels, when overexpressed. Required for cell cycle progression from G1 to S phases. Interacts with the SLBP/pre-mRNA complex but not with SLBP alone. Interacts with LSM11 in a U7 snRNP-dependent manner. Stable component of Cajal bodies (CBs). Colocalizes with SMN, coilin and U7 snRNA. The C2H2-type zinc finger 2 to 6 are necessary and sufficient for discrete Cajal bodies localization. The C2H2-type zinc finger 5 to 10 are necessary and sufficient for interaction with LSM11. The C2H2-type zinc finger 2 to 8 are necessary for interaction with the SLBP/RNA complex in the histone pre-mRNAs. The C2H2-type zinc finger 2 to 10 confer activity in histone pre-mRNA processing. Belongs to the krueppel C2H2-type zinc-finger protein family.