We recently described a new neonatal diabetes syndrome associated with congenital hypothyroidism, congenital glaucoma, hepatic fibrosis and polycystic kidneys. Here, we show that this syndrome results from mutations in GLIS3, encoding GLI similar 3, a recently identified transcription factor. In the original family, we identified a frameshift mutation predicted to result in a truncated protein. In two other families with an incomplete syndrome, we found that affected individuals harbor deletions affecting the 11 or 12 5'-most exons of the gene. The absence of a major transcript in the pancreas and thyroid (deletions from both families) and an eye-specific transcript (deletion from one family), together with residual expression of some GLIS3 transcripts, seems to explain the incomplete clinical manifestations in these individuals. GLIS3 is expressed in the pancreas from early developmental stages, with greater expression in beta cells than in other pancreatic tissues. These results demonstrate a major role for GLIS3 in the development of pancreatic beta cells and the thyroid, eye, liver and kidney.

Primary hyperoxaluria (PH) is an autosomal-recessive disorder of endogenous oxalate synthesis characterized by accumulation of calcium oxalate primarily in the kidney. Deficiencies of alanine-glyoxylate aminotransferase (AGT) or glyoxylate reductase (GRHPR) are the two known causes of the disease (PH I and II, respectively). To determine the etiology of an as yet uncharacterized type of PH, we selected a cohort of 15 non-PH I/PH II patients from eight unrelated families with calcium oxalate nephrolithiasis for high-density SNP microarray analysis. We determined that mutations in an uncharacterized gene, DHDPSL, on chromosome 10 cause a third type of PH (PH III). To overcome the difficulties in data analysis attributed to a state of compound heterozygosity, we developed a strategy of "heterozygosity mapping"-a search for long heterozygous patterns unique to all patients in a given family and overlapping between families, followed by reconstruction of haplotypes. This approach enabled us to determine an allelic fragment shared by all patients of Ashkenazi Jewish descent and bearing a 3 bp deletion in DHDPSL. Overall, six mutations were detected: four missense mutations, one in-frame deletion, and one splice-site mutation. Our assumption is that DHDPSL is the gene encoding 4-hydroxy-2-oxoglutarate aldolase, catalyzing the final step in the metabolic pathway of hydroxyproline.

Though numerous pieces of evidence point to major physiological roles for anion channels in plants, progress in the understanding of their biological functions is limited by the small number of genes identified so far. Seven chloride channel (CLC) members could be identified in the Arabidopsis genome, amongst which AtCLCe and AtCLCf are both more closely related to bacterial CLCs than the other plant CLCs. It is shown here that AtCLCe is targeted to the thylakoid membranes in chloroplasts and, in agreement with this subcellular localization, that the clce mutants display a phenotype related to photosynthesis activity. The AtCLCf protein is localized in Golgi membranes and functionally complements the yeast gef1 mutant disrupted in the single CLC gene encoding a Golgi-associated protein.

A diversity of mRNAs containing only short open reading frames (sORF-RNAs; encoding less than 30 amino acids) have been shown to be induced in growth and differentiation processes. The early nodulin gene enod40, coding for a 0.7-kb sORF-RNA, is expressed in the nodule primordium developing in the root cortex of leguminous plants after infection by symbiotic bacteria. Ballistic microtargeting of this gene into Medicago roots induced division of cortical cells. Translation of two sORFs (I and II, 13 and 27 amino acids, respectively) present in the conserved 5 and 3 regions of enod40 was required for this biological activity. These sORFs may be translated in roots via a reinitiation mechanism. In vitro translation products starting from the ATG of sORF I were detectable by mutating enod40 to yield peptides larger than 38 amino acids. Deletion of a Medicago truncatula enod40 region between the sORFs, spanning a predicted RNA structure, did not affect their translation but resulted in significantly decreased biological activity. Our data reveal a complex regulation of enod40 action, pointing to a role of sORF-encoded peptides and structured RNA signals in developmental processes involving sORF-RNAs.RNAs encoding only short open reading frames (sORFRNAs) have received considerable attention in recent years because they show a striking diversity in many cell types from various organisms. Several RNAs exhibit a function without being translated into proteins, for example, tRNAs, rRNAs, RNAs in ribozymes, and small nuclear RNAs from spliceosomes (reviewed in reference 8). However, a pentapeptideencoding sORF present in the 23S rRNA from Escherichia coli was recently shown to render this bacterium resistant to a specific antibiotic (40). In eukaryotes, several sORF-RNAs are induced at specific stages of development, suggesting their participation in various differentiation processes (7,14,18,31,38,40,44,46). Eukaryotic cells may use sORF-RNAs for the regulation of several cellular processes, as suggested by a thorough analysis of the yeast genome leading to identification of several new noncoding and sORF-containing RNAs (31). In eukaryotes, sORFs present in mRNAs are likely to be translated, since translation of mRNAs is achieved by a scanning mechanism in a 5Ј-to-3Ј direction. Indeed, there are several examples where translation of upstream sORFs regulates expression of the 3Ј ORF corresponding to the gene product (15,43). At the same time, very little is known about the fate of the encoded oligopeptides in the cell and whether translation of sORFs present in sORF-RNAs is relevant for gene activity. For example, even though a putative protein product of the H19 RNA was detected using immunological approaches (23), the main function of H19 seems to lie in the mRNA molecule rather than in the encoded protein (24).Leguminous plants have the ability to enter into symbiosis with N 2 -fixing bacteria (collectively called rhizobia) to form the root nodule. Development of this symbiotic organ depends on the coordinate expressio...