The primary structure of histone H4 from the nematode Caenorhabditis elegans

Unambiguous identification of histone H1 in Trypanosoma cruzi

“…Several motifs greatly enriched in lysine, alanine, and proline were found. This result is in accordance with data showing that, depending upon the source of the histone HI, the carboxy terminal domain comprises approximately 100 residues which are dominated by lysine (40 mol%), alanine (30 mol%), and proline (12 mol%) [Vanfleteren et al, 1988;Maeder and Bohm, 19911. Taking into account our previous and present evidence, we conclude that a histone H1 is present in T. cruzi chromatin showing the following characteristics: a) it is extracted from chromatin in 0.75 M PCA, 5% TCA, or 0.5 M NaCl [Toro and Galanti, 19881; it presents crossimmunoreactivity with an antiserum against histone H1 and possesses metachromasie proper of histones H1 [Toro and Galanti, 19881;c) its amino acid composition is similar to most histones Hl; d) its amino terminal residue is blocked; e) its carboxy terminal domain presents the motifs of amino acids expected for histones HI; f, its migration in SDS gel suggests a molecular weight in the range of the core histones from calf thymus; g) its migration in acid-urea gels is far ahead from the core histones [Toro and Galanti, 19901; it is composed of three or four variants [Toro and Galanti, 1990;Toro, 19911. The participation of histone H1 in the mechanisms leading to chromatin condensation [Thoma et al, 19791 and in the down-regulation of transcription by RNA polymerase I1 [Laybourn and Kadonaga, 1991, 19921 in higher eukaryotes has been established.…”

“…The sequences of these 8 peptides correspond t o motifs which are present in the carboxy terminal domain of all histones H1 described so far. However, each motif is present in this domain in a different number of repeats, depending upon the species since they present cluster organization [Vanfleteren et al, 1988;Maeder and Bohm, 19911. We do not know at present the number of each of the 8 repeats found in histone f i n its carboxy terminal domain.…”

“…Peptides obtained with proteases from this protein presented an amino acid sequence with a high degree of homology when compared to the carboxy terminal sequence of histone H1 from sea urchin gonads. It also presented the conserved motifs proper of most histones HI sequenced to date [Vanfleteren et al, 1988;Maeder and Bohm, 19911. Our results show that a histone H1 is present in T. cruzi chromatin. This protein shows most of the features previously described for this chromosomal protein in other species, except an unusual mobility in acid-urea and in SDS gels.…”

Germline-specific H1 variants: the “sexy” linker histones

“…Sperm chromatin (Strickland et al 1980) Echiura H1M Female germline and early embryo (Franks and Davis 1983) C. elegans H1.1/HIS-24 Male and female germline (Vanfleteren et al 1988) Present also in somatic cells all through development (Sanicola et al 1990 Xenopus, a sperm-specific H1fx variant has been reported, which shows significant homology to somatic H1x (Shechter et al 2009). Apart from vertebrates, a divergent spermspecific SpH1 variant has been reported in sea urchin (Strickland et al 1980) and, in Drosophila, the oocyte and early embryo dBigH1 variant is also present in testis, where its expression is largely restricted to spermatocytes (Pérez-Montero et al 2013).…”

Molecular and phylogenetic characterization of cytochromes c from Haemonchus contortus and Trichostrongylus vitrinus (Nematoda: Trichostrongylida)

“…In mammals and insects, CYT C proteins also play a key role in programmed cell death (apoptosis) (Chinnaiyan, 1999;Adrain and Martin, 2001;Ho and Zacksenhaus, 2004;Arama et al, 2006). CYT C proteins described from a range of taxa possess wellconserved functional domains (Vanfleteren et al, 1990;Allen et al, 2005), and multiple CYT C genes and isoforms have been identified. Some of these isoforms are expressed in somatic tissue, whilst testis-specific isoforms have been described from mammals and insects (Kim and Sabourin, 1986;Virbasius and Scarpulla, 1988;Narisawa et al, 2002;Schlecht et al, 2004;Arama et al, 2006).…”