In the mouse embryo, transcriptional activation begins during S/G2 phase of the
first cell cycle when paternal and maternal chromatin are still in separate nuclear
entities within the same cytoplasm. At this time, the male pronucleus exhibits
greater transcriptional activity than the female pronucleus. Acetylation of
histones in the nucleosome octamer exerts a regulatory influence on gene
expression.
Histones are the basic nuclear proteins responsible for the nucleosome structure within the chromosomal fiber in
eukaryotes anf histon H1.4 is a member of the histon H1 family.
NCBI Summary:
Histones are basic nuclear proteins that are responsible for the nucleosome structure of the chromosomal fiber in eukaryotes. Two molecules of each of the four core histones (H2A, H2B, H3, and H4) form an octamer, around which approximately 146 bp of DNA is wrapped in repeating units, called nucleosomes. The linker histone, H1, interacts with linker DNA between nucleosomes and functions in the compaction of chromatin into higher order structures. This gene is intronless and encodes a member of the histone H1 family. Transcripts from this gene lack polyA tails but instead contain a palindromic termination element. This gene is found in the large histone gene cluster on chromosome 6.
General function
DNA binding
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Cellular localization
Nuclear
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Ovarian function
Oogenesis
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Expression regulated by
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Ovarian localization
Oocyte
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Adenot PG, et al 1997 reported the differential H4 acetylation of paternal and maternal chromatin
precedes DNA replication and differential transcriptional activity
in pronuclei of 1-cell mouse embryos.
Immediately
following fertilization, hyperacetylated H4 was associated with paternal but not
maternal chromatin while, in parthenogenetically activated oocytes, maternal
chromatin became hyperacetylated.
These results suggest that sperm
chromatin initially out-competes maternal chromatin for the pool of
hyperacetylated H4 in the oocyte, that hyperacetylated H4 participates in the
process of histone-protamine exchange in the zygote, and that differences in H4
acetylation in male and female pronuclei during G1 are translated across DNA
replication to transcriptional differences in S/G2. Prior to fertilization, neither
paternal nor maternal chromatin show memory of H4 hyperacetylation patterns
but, by the end of the first cell cycle, before major zygotic genome activation at the
2-cell stage, chromosomes already show hyperacetylated H4 banding patterns.