Adapter protein for the cul3 E3 ubiquitin-protein ligase complex. Promotes the export of zbtb16/plzf from the nucleus to the cytoplasm and targets zbtb16/plzf for ubiquitination and degradation. Up-regulates neurog1 expression and antagonizes zbtb16/plzf, to promote neurogenesis. Interacts with cul3. Interacts (via BTB domain) with zbtb16/plzf. Present mainly, but not excusively in the cytoplasm. Expressed in the developing central nervous system. Expressed during primary neurogenesis. At the 3 somite stage (3s), expressed in rostrocaudal stripes in the posterior neural plate characteristic of the lateral zone, intermediate zone, and medial zone of primary neurogenesis. At 14s and 20 hpf, widely expressed in the spinal cord. By 24 hpf, becomes restricted to the posterior spinal cord. Expression also occurs in a dynamic segmental pattern in the hindbrain, at the mid-hindbrain boundary, cranial ganglia, midbrain, and forebrain. Isoform 1: Expressed throughout early development. Isoform 2: up-regulated from 9 hpf, when neurogenesis is initiated. Morpholino knockdown of both isoform 1 and isoform 2 leads to a major decrease in the expression of neurog1 and downstream markers of neuronal differentiation. Knockdown of either isoform alone leads to a mild decrease in the expression of late markers of neurogenesis, but has no detectable effect on neurog1 expression. Truncated N-terminus.