XSPR-1 and XSPR-2, novel Sp1 related zinc finger containing genes, are dynamically expressed during Xenopus embryogenesis

Proteins related to the human transcription factor Sp1 are characterized by the presence of a highly conserved zinc finger domain consisting of three C2H2 type zinc fingers. Here we describe two Xenopus laevis cDNAs, which encode novel Sp1-related C2H2 type zinc finger transcription factors named XSPR-1 and XSPR-2. Structurally, XSPR-1 and XSPR-2 are closely related to the murine Sp5, which interacts genetically with Brachyury (Dev. Biol. 227 (2000) 358). XSPR-1 and XSPR-2 are expressed in broad and dynamic patterns during early development. Starting at gastrulation, XSPR-1 transcripts are restricted to the non-involuting marginal zone, and, at later stages, to the neuroectoderm, forebrain, otic vesicles and the midbrain/hindbrain boundary. In contrast, XSPR-2 expression is found predominantly within the presumptive mesoderm during gastrulation. At tailbud and tadpole stages, XSPR-2 is expressed exclusively in the tip of the tail.