The novel transcription factor gene Sp5 exhibits a dynamic and highly restricted expression pattern during mouse embryogenesis

Abstract

We describe the sequence and expression pattern of Sp5, a novel member of the vertebrate Sp1 transcription factor gene family which consists of at least five members. This gene family is characterized by a highly conserved domain which is formed by three Zn fingers, which bind to the GC box or the GT/CACC box in the promoter of many genes. These boxes are important cis-acting elements required for the expression of the respective genes. In vitro experiments indicate that the Sp1 transcription factors act by influencing the methylation state of the DNA, or by direct interactions with other promoter specific transcription factors. Despite intensive research, the results from in vivo experiments, including targeted gene inactivation, have been difficult to explain. This may be due to possible redundancies and interferences with other transcription factors of this gene family. Here, we report the isolation of the mouse Sp5 gene, a novel Sp1 homolog. Its sequence indicates that Sp5 is a possible link between Sp1 and the closely related BTEB/KLF gene family. We provide detailed information of its highly dynamic expression pattern during mouse embryogenesis in the developing brain, the spinal cord, the trigeminal ganglia, the somites and additional sites outside the nervous system starting from embryonic day 7.25 (E7.25) up to E10.5.

Sp8andSp9, two closely relatedbuttonhead-like transcription factors, regulateFgf8expression and limb outgrowth in vertebrate embryos

“…A similar scenario to gene evolution has been proposed for the Tbx2 subfamily genes, Tbx2-Tbx5 (Agulnik et al, 1996). Our finding that Sp5 is not linked to other Sp genes supports a previously proposed evolutionary mechanism of Sp genes, in which Sp5 might be an evolutionary link between the Sp family and KLF family, another Zn finger factor family whose primary structure of the Zn finger domain is related to that of Sp family but lacks the btd domain (Ravasi et al, 2003;Treichel et al, 2001). Genetic and embryological analyses have revealed that Fgf10-Fgfr2b in tandem is pivotal for inducing the expression of Fgf8 in the AER precursor cells, migration of AER precursors from the surface ectoderm to the dorsoventral boundary, and formation of the AER (Gorivodsky and Lonai, 2003;Min et al, 1998;Ohuchi et al, 1997;Sekine et al, 1999).…”

Wnt/β-catenin regulation of the Sp1-related transcription factor sp5l promotes tail development in zebrafish

“…(Pieler and Bellefroid, 1994). Sp1 proteins bind to GC-rich promoter regions, and while some members of this protein family are expressed ubiquitously and are thought to be required generally as enhancers of transcription, others, including members of the Sp5 subfamily, are expressed in restricted domains and are thought to participate in specific processes during development (Bell et al, 2003;Briggs et al, 1986;Harrison et al, 2000;Tallafuss et al, 2001;Treichel et al, 2001;Treichel et al, 2003). Our data strongly suggest that sp5l functions downstream of Wnts in zebrafish tail development.…”

mBtd is required to maintain signaling during murine limb development

“…The btd homolog was isolated by a PCR-based approach, using degenerated primer pairs within the btd zinc finger box (Treichel et al 2001). A resulting 230-bp DNA fragment was subsequently used to screen an embryonic day (E)8.5 mouse cDNA library.…”