spalt encodes an evolutionarily conserved zinc finger protein of novel structure which provides homeotic gene function in the head and tail region of the Drosophila embryo.

Abstract

The region specific homeotic gene spalft (sal) of Drosophila melanogaster promotes the specification of terminal pattern elements as opposed to segments in the trunk. Our results show that the previously reported sal transcription unit was misidentified. Based on P-element mediated germ line transformation and DNA sequence analysis of sal mutant alleles, we identified the transcription unit that carries sal function. sal is located close to the misidentified transcription unit, and it is expressed in similar temporal and spatial patterns during embryogenesis. The sal gene encodes a zinc finger protein of novel structure composed of three widely spaced 'double zinc finger' motifs of internally conserved sequences and a single zinc finger motif of different sequence. Antibodies produced against the sal protein show that sal is first expressed at the blastoderm stage and later in restricted areas of the embryonic nervous system as well as in the developing trachea. The antibodies detect sal homologous proteins in corresponding spatial and temporal patterns in the embryos of related insect species. Sequence analysis of the sal gene of Drosophila viruis, a species which is phylogenetically separated by -60 million years, suggests that the sal function is conserved during evolution, consistent with its proposed role in head formation during arthropod evolution.

Identification of the nuclear localization signal of SALL4B, a stem cell transcription factor

“…[1][2][3] SALL4 expression is high in stem cells and downregulated during development, and its expression is largely absent in most adult tissues. [4][5][6] As a stem cell transcription factor, SALL4 is capable of increasing reprogramming efficiency of somatic cells to become induced pluripotent stem cells.…”

Murine inner cell mass-derived lineages depend on Sall4 function

“…Recently, a reciprocal interaction between Oct4 and Cdx2 has been shown to be essential for the establishment of the trophectoderm lineage (15). The Spalt͞Sall transcription factor family was initially discovered in Drosophila and later found to be conserved in Caenorhabditis elegans, Xenopus, fish, mouse, and humans (16). In Drosophila, Spalt proteins possess homeotic function during development and are required in photoreceptor differentiation and planar cell polarity (17).…”

Transcriptional Activation of the SALL1 by the Human SIX1 Homeodomain during Kidney Development

“…Each homologue is expressed during embryonic development, as well as in specific adult tissues. Drosophila SAL mutation leads to the incomplete transformation of head and tail segments into trunk-like characters and the establishment of larval legs and discs (19,20).…”