Mutations in NMNAT1 cause Leber congenital amaurosis and identify a new disease pathway for retinal degeneration

Leber congenital amaurosis (LCA) is a blinding retinal disease that presents within the first year after birth. Using exome sequencing, we identified mutations in the nicotinamide adenine dinucleotide (NAD) synthase gene NMNAT1 encoding nicotinamide mononucleotide adenylyltransferase 1 in eight families with LCA, including the family in which LCA was originally linked to the LCA9 locus. Notably, all individuals with NMNAT1 mutations also have macular colobomas, which are severe degenerative entities of the central retina (fovea) devoid of tissue and photoreceptors. Functional assays of the proteins encoded by the mutant alleles identified in our study showed that the mutations reduce the enzymatic activity of NMNAT1 in NAD biosynthesis and affect protein folding. Of note, recent characterization of the slow Wallerian degeneration (Wld(s)) mouse model, in which prolonged axonal survival after injury is observed, identified NMNAT1 as a neuroprotective protein when ectopically expressed. Our findings identify a new disease mechanism underlying LCA and provide the first link between endogenous NMNAT1 dysfunction and a human nervous system disorder.     

Chromosomal heteromorphism and female heterogamety in the marbled newtTriturus marmoratus (Latreille, 1800)

Riassunto Il bivalente lampbrush I diTriturus marmoratus è costituito da 2 cromosomi partner di diversa lunghezza a presenta loops eteromorfi lungo una regione sempre sprovvista di chiasmi. Si può quindi ritenere che tale bivalente sia costituito dagli eterocromosomi Z e W.

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With financial support by C.N.R., Rome.     

Presence of thyrotropin-releasing hormone in porcine and bovine retina

Summary The thyrotropin-releasing hormone (TRH) has been found in porcine and in bovine retina, and it is indistinguishable from synthetic TRH in its immunological and biological properties. The role of retinal TRH is unknown, it probably acts as a neurotransmitter.     

Lampbrush chromosomes from semi-albino crested newts,Triturus Cristatus Carnifex (Laurenti)

Riassunto Sono stati studiati i «lampbrush chromosomes» di mutanti semi-albini diTriturus cristatus carnifex. Il rilevamento degli organizzatori nucleolari ha permesso il completamento delle mappe cromosomiche della specie.

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This work was financially supported by C.N.R., Rome.     

Unsaponifiable constituents inSpirographis spallanzani

Riassunto L'insaponificabile del muscolo diSpirographis spallanzani contiene accanto a steroli e tocoferolo, un composto di natura chinonica avente molte proprietà in comune con gli ubichinoni. Anche il tocoferilchinone è stato identificato negli estratti. Si ritiene però che esso si formi dal tocoferolo durante il procedimento di estrazione.

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This work has been partially supported by a U.S. Public Health Service Grant (R.G. 4845). The authors gratefully acknowledge suggestions and criticisms from Dr.Hemming and Dr.Pennock, Biochemistry Department, Liverpool.     

Morphology of the mitotic chromosomes of embryos and of adults of Italian alpine newtTriturus alpestris apuanus (Bonaparte)

Riassunto E' stata descritta la diversa morfologia dei cromosomi mitotici diTriturus alpestris apuanus, studiati in blastomeri e in cellule somatiche di individui adulti.

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With financial support by C.N.R., Rome.