Dental crowding in a prehistoric population.

The aims of this study were to investigate dental crowding from the Copper Age and examine the extent and patterns of wear. Crowding was estimated in 43 adult mandibles using Little's irregularity index. Dental wear, dental diameters, arch width and the presence of third molars were also studied as possible aetiological factors for crowding. The remains were found at the archaeological site of Roaix, located in the south of France. Radiocarbon dating indicated that the lower layer was from 2150 +/- 140 years BC (date +/- 1 standard deviation) and the upper level from 2090 +/- 140 years. The graves were estimated to contain the remains of 150 adults and 50 children. Forty-three intact mandibles were used for this study. All of the mandibles presented incisor crowding with a majority of minimal and moderate irregularities, but in seven cases there were extreme irregularities and in two canine impaction was observed. These results are in contrast with the literature where it is reported that malocclusions were rare in prehistoric populations. The findings of this study suggest that crowding may be of a genetic origin and might not be caused by excessive tooth size or changes in environmental factors (masticatory activity).

Alternative promoter usage and splicing of ZNF74 multifinger gene produce protein isoforms with a different repressor activity and nuclear partitioning.

We have previously shown that ZNF74, a candidate gene for DiGeorge syndrome, encodes a developmentally expressed zinc finger gene of the Kruppel-associated box (KRAB) multifinger subfamily. Using RACE, RT-PCR, and primer extension on human fetal brain and heart mRNAs, we here demonstrate the existence of six mRNA variants resulting from alternative promoter usage and splicing. These transcripts encode four protein isoforms differing at their N terminus by the composition of their KRAB motif. One isoform, ZNF74-I, which corresponds to the originally cloned cDNA, was found to be encoded by two additional mRNA variants. This isoform, which contains a KRAB motif lacking the N terminus of the KRAB A box, was devoid of transcriptional activity. In contrast, ZNF74-II, a newly identified form of the protein that is encoded by a single transcript and contains an intact KRAB domain with full A and B boxes, showed strong repressor activity. Deconvolution immunofluorescence microscopy using transfected human neuroblastoma cells and nonimmortalized HS68 fibroblasts revealed a distinct subcellular distribution for ZNF74-I and ZNF74-II. In contrast to ZNF74-I, which largely colocalizes with SC-35 in nuclear speckles enriched in splicing factors, the transcriptionally active ZNF74-II had a more diffuse nuclear distribution that is more characteristic of transcriptional regulators. Taken with the previously described RNA-binding activity of ZNF74-I and direct interaction with a hyperphosphorylated form of the RNA polymerase II participating in pre-mRNA processing, our results suggest that the two ZNF74 isoforms exert different or complementary roles in RNA maturation and in transcriptional regulation.

Isolation of a zinc finger gene consistently deleted in DiGeorge syndrome.

DiGeorge syndrome is a human developmental disorder resulting in hypoplasia of the thymus and parathyroids, and conotruncal heart defects. We recently isolated four genes with zinc finger DNA binding motifs mapping to chromosome 22q11.2 DiGeorge critical region. We now report that one of them, ZNF74 gene, is hemizygously deleted in 23 out of 24 DiGeorge syndrome patients tested. ZNF74 mRNA transcripts are detected in human and mouse embryos but not in adult tissues. Sequence analysis of a corresponding cDNA reveals an an open reading frame encoding 12 zinc finger motifs of the Kruppel/TFIIIA type as well as N-terminal and C-terminal non-zinc finger domains. These results suggest that changes in the dosage of a putative transcription factor through ZNF74 hemizygous deletion may be critical for DiGeorge developmental anomalies.

[Comparative study on the digestion of radiolabelled vicilin, legumin and lectin of Pisum sativum in the rat]. / Etude comparée de la digestion des viciline, légumine et lectine radiomarquées de Pisum sativum chez le rat.

Storage proteins, vicilin, legumin as well as the lectin, purified from pea seed proteins, were radiolabelled with [14C]- or [3H]-formaldehyde, then mixed with the pea flour which was incorporated in a liquid meal and given to rats through a gastric tubing. Radiolabelled casein (75% of the total proteins in the meal) and triolein were added to the meal and the animals were killed after 2 and 7 h. Samples were taken from the stomach and intestinal contents and from the intestinal mucosa and the liver. 2 h: gastric emptying and intestinal absorption from vicilin and legumin materials were as high as for casein. 7 h: in the colon contents an excess of labelled vicilin and legumin (2.9 and 2.6% of the radioactive dose from the meal) was observed compared to casein (1.5%). The pea lectin disappeared slowlier from the intestinal contents than did the three other radiolabelled proteins (2 h) which gave the highest radioactive materials in the livers. The lectin did not interact with the intestinal mucosa but it was less hydrolysed than the three other proteins tested and 15% of the dose reached the colon (7 h). This lectin could have been adsorbed on pancreatic enzymes such as a lipase, but radiolabelled triolein did not produce radioactive material in the colon, demonstrating that lectin or other pea proteins, in these experiments did not inhibit this lipase. Short-time experiments (2 h, 7 h) were sufficient to describe and compare the digestion of three radiolabelled pea proteins.