Gene Networks Database
purpuratus Genes in Development: Histone genes
H1-gamma is a gene encoding the late histone subtype.
The H1-gamma gene appears to be a unique sequence gene
that is not tightly linked to the core histone genes.
This gene is present in a single copy per haploid genome
and encodes an mRNA of 752 nucleotides (Knowles et al.,1987).
H1-gamma belongs to the late histone subtype.
The primary structure of this protein
is 209 amino acids in length.
It has the tripartite structure (nose, head
and tail) typical of this class of histones.
The head regions (amino acids 17 to 85) are believed to
be globular domains.
The 3` tail region of H1-gamma is extremely basic,
consisting almost exclusively of lysine, alanine, and
proline. H1-gamma contains no serine residues in the
C-terminal tail. The last 66 amino acids of
H1-gamma are composed almost entirely of two repeated
pentapeptides. The peptide PAAKK is repeated four times
between amino acids 151 and 171, and the related
peptide KPAKK is repeated five times from amino acid
177 to the C-terminus.
The large nomber of lysine residues gives H1-gamma
a net positive charge of 70 (Knowles et al., 1986).
There are 3,900 stored maternal H1-gamma mRNA
transcripts per egg.
The number of H1-gamma transcripts
per embryo rises by 9.5 h postfertilization, but the
maximum rate of accumulation (4,300 molecules per min
per embryo) occurs in the late-blastula-stage embryo
between 14 and 21 h after fertilization. The number of
H1-gamma mRNA molecules peaks 21 h after fertilization
when there are 2.0 X 10(6) molecules per embryo
(a 500-fold increase) and then decreases over the next
3.25 h to 1.3 million molecules per embryo.
Between 24 and 82 h after fertilization the number of H1-gamma
transcripts declines steadily (210 molecules per min
per embryo) to reach approximately 5.4 X 10(5) H1-gamma
mRNAs by 82 h postfertilization (Knowles et al.,1987).
The relative amounts of the H1-gamma mRNA during development
Method: Nothern blot hybridization.
Reference: Knowles et al., 1987.
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