Hcc-1 is a novel component of the nuclear matrix with growth inhibitory function.

Hcc-1 is a novel nuclear protein containing the SAF-box DNA-binding domain. It binds to both double-stranded and single-stranded DNA with higher affinity for the single-stranded form. In addition, it also binds specifically to scaffold/matrix attachment region DNA. These nucleic acid-binding characteristics suggest a potential function for Hcc-1 as a component of the heterogeneous ribonucleoprotein complex. Using a yeast two-hybrid screen, two DEAD-box RNA helicases, BAT1 and DDX39, were identified as proteins that interact with Hcc-1. Interactions with these RNA helicases suggested a role for Hcc-1 in nucleic acid biogenesis. Expression of Hcc-1 in the HEK293 cell line resulted in a slower growth rate compared to controls (p = 0.0173) and an accumulation of cells at the G2/M phase (p = 0.0276 compared to control HEK293 cells). Taken together, these results suggest a role for Hcc-1 in growth regulation and nucleic acids metabolism.