Spindlin (Spin) is a novel maternal transcript present in the unfertilised egg and early embryo [1]. The Y-linked spermiogenesis -specific transcript (Ssty) is also expressed during gametogenesis and forms part of this Pfam family. Members of this family contain three copies of this 50 residue repeat. The repeat is predicted to contain four beta strands.

1: Spindlin, a major maternal transcript expressed in the mouse during the transition from oocyte to embryo. Oh B, Hwang SY, Solter D, Knowles BB; Development 1997;124:493-503. PMID:9053325

2: The Spin/Ssty repeat: a new motif identified in proteins involved in vertebrate development from gamete to embryo. Staub E, Mennerich D, Rosenthal A; Genome Biol 2002;3:0-0. PMID:11806826