Characterization of the chicken histone H1 gene complement. Generation of a complete set of vertebrate H1 protein sequences

Sequence analysis of four chicken H1 histone genes described here completes the characterization of the full complement of six H1 genes in the chicken genome. Each of the six genes codes for a different H1 protein sequence, and these range in size from 217 to 224 amino acids. The proteins are distinct in sequence from the H1-related chicken H5 protein and appear to be analogous to the standard somatic mammalian H1 subtypes. The protein sequence data deduced from the genes represent the first complete set of vertebrate H1 protein sequences. Comparison of the chicken H1 gene noncoding sequences with each other and with H1 gene sequences from other organisms reveals conservation of an H1 gene-specific element, a G-rich element, and histone gene-specific 3' elements. Additional sequences are conserved between H1 genes of the chicken and other vertebrates. Comparisons also reveal variation in promoter and 3' elements between chicken genes that could play a role in the differential expression of H1 gene protein products.     

The basalis of the primate endometrium: a bifunctional germinal compartment

Radioautographic analysis of epithelial and stromal cell proliferation in the primate endometrial functionalis and basalis (rhesus monkey) has identified horizontal zonal patterns of mitotic activation and inhibition during natural menstrual cycles. At 1 h after a single i.v. injection of [3H]thymidine, mitotic activity in endometrial biopsies (hysterotomy) was determined on 9 days from the late proliferative to the late luteal phase (-2 days to + 14 days relative to the estrogen [E2]peak). Labeling indices (LIs) were determined within glandular segments of the 4 horizontal endometrial zones: Transient functionalis Zone I (luminal epithelium) and Zone II (uppermost gland); Germinal basalis: Zone III (middle gland) and Zone IV (basal gland). The size of the dividing epithelial populations (LI) differed zonally. During E2 dominance (-2 days to +3 days), the epithelial LIs of functionalis I (10 +/- 0.3%) and II (9.8 +/- 1.0%) were greater than those of basalis III (5.8 +/- 0.2%) and basalis IV (3.7 +/- 0.8%). During progesterone (P) dominance (+5 days to +14 days), epithelial mitosis was strongly inhibited in functionalis I (4.3 +/- 1.9%), functionalis II (0.8 +/- 0.2%), and basalis III (1.4 +/- 0.5%). Thus germinal basalis III was linked functionally with transient functionalis I and II by periovulatory uniformity in epithelial proliferation and postovulatory mitotic inhibition. A unique mitotic pattern set basalis IV apart from other zones by a steady rise in LI from 1% (-2 days) to 11% (+10 days). The LIs for stromal fibroblasts remained quite uniform in basalis IV but varied in other zones. Thus the postovulatory primate basalis was a distinct bipartite compartment in which the mitotic rate in basalis IV glandular epithelium increased steadily whereas that of basalis III was strongly inhibited. The remarkable enhancement of epithelial mitotic activity in basalis IV may reflect expansion of the stem-progenitor cell population for gestational growth or for post-menstrual regeneration.     

Antigenicity of a proteolytic enzyme of Fasciola hepatica

The possibility was examined of using a haemoglobinase released during in vitro incubation of adult Fasciola hepatica for immunodiagnosis of fascioliasis. By SDS gel electrophoresis the enzyme appeared as two closely migrating bands with a molecular weight of approximately 27,000 daltons. After Western blotting the bands reacted with serum from rats infected with F. hepatica and mice infected with Schistosoma mansoni. The enzyme was therefore not a good antigen for immunodiagnosis.     

K+ accumulation in the space between giant axon and Schwann cell in the squid Alloteuthis. Effects of changes in osmolarity.

In a train of impulses in squid giant axon, accumulation of extracellular potassium causes successive afterhyperpolarizations to be progressively less negative. In Loligo, Frankenhaeuser and Hodgkin had satisfactorily accounted for the characteristics of this effect with a model in which the axon is surrounded by a space, width theta, and a barrier of permeability P. In axons isolated from Alloteuthis, we found that the model fitted the observations quite well. Superfusing the axon with hypotonic artificial seawater (ASW) caused theta and P to decrease, and, conversely, hypertonic ASW caused them to increase: this would be the case if both the space and the pathway through the barrier were extracellular. In some cases, in normal ASW, the afterhyperpolarizations in a train decreased very little, less than 0.7 mV. In these extreme cases, theta was estimated to be 190 nm and P to be 7 x 10(-4) cm s-1, both several times the values of 30 nm and 6 x 10(-5) cm s-1 estimated by Frankenhaeuser and Hodgkin. We suggest that in vivo the periaxonal space may be considerably wider than that seen in conventionally fixed squid tissue.     

Fluorescent and Ferritin Labelling of Cuticle Surface Carbohydrates of Caenorhabditis elegans and Panagrellus redivivus

Caenorhabditis elegans and Panagrellus redivivus were investigated for surface carbohydrates using fluorescent-labelled and ferritin-labelled lectins. Rhodamine-labelled Concanavalin A was specifically located in the cephalic region of both species. Rhodamine-labelled wheat germ agglutinin was located over the entire cuticle of P. redivivus but was absent on C. elegans. Rhodamine-labelled peanut agglutinin and Limax flavus agglutinin did not label nematodes of either species. Galactose and sialic acid were not detected on either species, whereas mannose-glucose residues were specifically localized in the head areas of both species. No detectable N-acetylglucosamine occurred on C. elegans, but it was evenly distributed over the cuticle surface of P. redivivus.     

Chromosomal organization of chicken histone genes: preferred associations and inverted duplications.

We present a detailed picture of the disposition of core and H1 histone genes in the chicken genome. Forty-two genes were located within four nonoverlapping regions totalling approximately 175 kilobases and covered by three cosmid clones and a number of lambda clones. The genes for the tissue-specific H5 histone and other variant histones were not found in these regions. The longest continuous region mapped was 67 kilobases and contained 21 histone genes in five dissimilar clusters. No long-range repeat was evident, but there were preferred associations, such as H1 genes with paired, divergently transcribed H2A-H2B genes and H3-H4 associations. However, there were exceptions, and even when associations such as H1-H2A-H2B we maintained, the order of those genes within a cluster may not have been. Another feature was the presence of three (unrelated) clusters in which genes were symmetrically ordered around central H3 genes; in one such cluster, the boundaries of a duplicated H2A-H4 gene pair contained related repeat sequences. Despite the dispersed nature of chicken histone genes, the number of each type was approximately equal, being represented as follows: 6 H1, 10 H2A, 8 H2B, 10 H3, and 8 H4.