INTS13 Mutations Causing a Developmental Ciliopathy Disrupt Integrator Complex Assembly

Oral-facial-digital syndromes (OFD) are a heterogeneous group of congenital disorders characterized by malformations of the face and oral cavity, and digit anomalies. To date, mutations in 12 ciliary-related genes have been identified to cause several OFD types suggesting OFDs constitute a subgroup of developmental ciliopathies. Through homozygosity mapping and exome sequencing performed on two families with variable OFD type 2, we identified distinct germline mutations in INTS13, a subunit of the Integrator Complex. This 14-component complex associates with RNAPII and can cleave nascent RNA to modulate gene expression. We determined that INTS13 utilizes a discrete domain within its C-terminus to bind the Integrator cleavage module, which is disrupted by the identified germline INTS13 mutations. Depletion of INTS13 disrupts ciliogenesis in human cultured cells and causes dysregulation of a broad collection of ciliary genes. Accordingly, its knockdown in Xenopus embryos lead to motile cilia anomalies. Altogether, we show that mutations in INTS13 cause an autosomal recessive ciliopathy, which reveal key interactions within Integrator components. Overall design: Examination of 9 samples (3 biological replicate sets of ARPE-19 cells: control knockdown; IntS13 body targeting knockdown; IntS13 utr targeting knockdown)