High mobility group 1 (HMG1) protein in mouse preimplantation embryos

Abstract

High mobility group 1 protein (HMG1) has traditionally been considered a structural component of chromatin, possibly similar in function to histone H1. In fact, at the onset of Xenopus and Drosophila development, HMG1 appears to substitute for histone H1: HMG1 is abundant when histone H1 is absent after the midblastula transition histone H1 largely replaces HMG1. We show that in early mouse embryos the expression patterns of HMG1 and histone H1 are not complementary. Instead, HMG1 content increases after zygotic genome activation at the same time as histone H1. HMG1 does not remain associated to mitotic chromosomes either in embryos or somatic cells. These results argue against a shared structural role for HMG1 and histone H1 in mammalian chromatin.

HMG chromosomal proteins in development and disease

“…These observations suggest that HMGB1 has a role in maintaining the chromatin structure, especially in early embryogenesis. However, neither HMGB1 protein nor mRNA is stored in the mouse oocyte, suggesting that the role of HMGB1 in the early embryogenesis of mammalians is different from those in other species [34].…”

Regulated expression and subcellular localization of HMGB1, a chromatin protein with a cytokine function

“…HMGB1 is a fairly compact gene both in mouse and humans [51, 52]. Its transcription starts at the two‐cell stage in mice [53]. Human HMGB1 has a very strong TATA‐less promoter, more than 18‐fold more active than the SV40 promoter [54].…”

“…Regulation at the level of HMGB1 mRNA translation or mRNA stability is suggested by the existence of long 3′ untranslated regions, that are highly conserved between species [63]. There are three HMGB1 mRNAs, which result from the use of different polyadenylation signals [51–53], but no conditions have been found so far in which the three mRNAs change their relative abundance. The stabilities of these three mRNAs are also unknown.…”

High Mobility Group Box 1 Regulates Uterine Decidualization through Bone Morphogenetic Protein 2 and Plays a Role in Kruppel-Like Factor 5-Induced Stromal Differentiation

“…In addition to its nuclear role, Hmgb1 could also act as an extracellular signaling molecule to modulate the inflammation, immune response, autophagy and cancer [9][10][11]. Further analysis evidenced that Hmgb1 was highly expressed in mouse blastocyst and implicated in the regulation of preimplantation embryo development [12,13]. Meanwhile, abundant Hmgb1 expression was also observed in human and rat uteri during pre-receptive phase, while receptive uteri exhibited a decline [14].…”