The plant homeodomain finger protein MESR4 is essential for embryonic development in Drosophila

Abstract

Misexpression Suppressor of Ras 4 (MESR4), a plant homeodomain (PHD) finger protein with nine zinc-finger motifs has been implicated in various biological processes including the regulation of fat storage and innate immunity in Drosophila. However, the role of MESR4 in the context of development remains unclear. Here it is shown that MESR4 is a nuclear protein essential for embryonic development. Immunostaining of polytene chromosomes using anti-MESR4 antibody revealed that MESR4 binds to numerous bands along the chromosome arms. The most intense signal was detected at the 39E-F region, which is known to contain the histone gene cluster. P-element insertions in the MESR4 locus, which were homozygous lethal during embryogenesis with defects in ventral ectoderm formation and head encapsulation was identified. In the mutant embryos, expression of Fasciclin 3 (Fas3), an EGFR signal target gene was greatly reduced, and the level of EGFR signal-dependent double phosphorylated ERK (dp-ERK) remained low. However, in the context of wing vein formation, genetic interaction experiments suggested that MESR4 is involved in the EGFR signaling as a negative regulator. These results suggested that MESR4 is a novel chromatin-binding protein required for proper expression of genes including those regulated by the EGFR signaling pathway during development. genesis 53:701-708, 2015. © 2015 Wiley Periodicals, Inc.

Drosophila MESR4 Gene Ensures Germline Stem Cell Differentiation by Promoting the Transcription of bag of marbles

“…However, we found that the PHD finger is dispensable for the MESR4 function in germ cell differentiation. Consistent with our observation, previous studies failed to detect the direct association of MESR4 with the modified histones [49]. While we cannot completely exclude that MESR4 is involved in chromatin remodeling, we prefer an alternative hypothesis for the MESR4 function.…”

“…It is able to suppress the constitutively activated Ras-MAPK pathway [47] or the FGF-signaling [48]. In addition, MESR4 is required for the proper control of EGFR/ERK signaling during embryonic development and wing formation [49]. In the adult female GSC niche, the EGFR/ERK pathway is active in the escort cells, and limits the Dpp gradient to the anterior tip of the niche where the GSCs reside [50].…”

Genome wide survey, evolution and expression analysis of PHD finger genes reveal their diverse roles during the development and abiotic stress responses in Brassica rapa L.

“…The PHD finger was first identified in Arabidopsis thaliana transcription factor HAT3.1 (a homeodomain-containing protein) and its maize homolog Zmhox1a in 1993 [22]. Since then, many other PHD-finger proteins have been identified in various eukaryotes, including the yeast [23, 24], Drosophila [25, 26] and human [12, 27, 28]. The PHD finger can be defined as a Cys-rich domain of approximately 50~80 amino acids with spatially conserved 8 metal ligands arranged as unique Cys4-His-Cys3 pattern in 4 pairs which can chelate two Zn 2+ atoms and form a cross-brace structure [13, 29, 30].…”