ABSTRACT
PURPOSE: To characterize the disease expression of an autosomal recessive human retinal degeneration associated with a mutation in TULP1 (tubby-like protein 1), a gene with currently unknown function. METHODS: Homozygotes and heterozygotes from an extended Dominican kindred with a TULP1 splice-site gene mutation (IVS14+1,G-->A) were studied clinically and with visual function tests. Sequence analysis of TULP1 was also performed in unrelated patients with severe retinal degeneration from a North American clinic population. RESULTS: Homozygotes had nystagmus, visual acuity of 20/200 or worse, color vision disturbances, bull's eye maculopathy, and peripheral pigmentary retinopathy. Younger patients had a relatively wide extent of kinetic visual fields; older patients had only peripheral islands. No rod function was measurable by psychophysics in any of the patients; markedly reduced cone function was detectable across the visual field of younger patients and in the remaining peripheral islands of older patients. Rod and cone electroretinograms (ERGs) were not detectable using standard methods; microvolt-level cone ERGs were present in some patients. Heterozygotes had normal visual function. No putative pathogenic sequence changes in TULP1 were observed in North American patients with comparably severe retinal phenotypes, mainly in the diagnostic category of Leber congenital amaurosis. CONCLUSIONS: This TULP1 splice-site mutation in homozygotes causes early-onset, severe retinal degeneration involving macular and peripheral cones and rods. The constellation of phenotypic findings suggests that the TULP1 gene product is critically important for normal photoreceptor function and may play a role in retinal development.
Subject(s)
Alternative Splicing/genetics , Eye Proteins/genetics , Point Mutation , Retinal Degeneration/genetics , Adolescent , Adult , Child , Color Vision Defects/genetics , Color Vision Defects/physiopathology , DNA/analysis , Electroretinography , Female , Fundus Oculi , Humans , Male , Nystagmus, Pathologic/genetics , Nystagmus, Pathologic/physiopathology , Pedigree , Photoreceptor Cells, Vertebrate/physiology , Polymerase Chain Reaction , Retinal Degeneration/physiopathology , Visual Acuity , Visual FieldsABSTRACT
Mildew resistance in the ornamental apple 'White Angel' was found to be determined by complementary genes. The gene R w was found to be necessary for the expression of resistance controlled by the resistance gene Pl w . The close linkage between the isoenzyme gene, Lap-2, for leucine aminopeptidase and P1 w was confirmed. The efficiency of Lap-2 as a marker in screening for mildew resistance is limited, as it cannot account for susceptible plants with the r w r w P1 w p1 w genotype. It has, however, an important role to play in combining resistance genes from different sources. The genotypes of 'White Angel' (R w r w , Pl w pl w , Lap-2an), 'Jester' (R w r w , p1 w p w , Lap-2an) 'Katja' (R w r w ,p1 w p1 w , Lap-2an) and 'Gloster 69' (r w r w , p1 w p1 w , Lap-2an) were determined. It also appeared that R w might influence Lap-2 activity in young seedlings.
ABSTRACT
The S incompatibility system of apple was confirmed through the application of the gene Got-1 for glutamate oxaloacetate transaminase as a marker for the S locus. The 11S alleles proposed by Kobel et al. (1939) were confirmed through anomalous segregations for Got-1 observed in 14 semi-compatible crosses and regular segregations observed in 2 fully compatible crosses. The S allele genotypes of 'Idared' (S 3 S 7), 'Cox' (S 5 S 9) and 'Fiesta' (S 3 S 5) were determined and found to fall within the original series. By associating parental incompatibility genotypes with the segregation of Got-1 alleles, we were able to deduce the coupling of S and Got-1 alleles in 9 varieties.
ABSTRACT
To demonstrate the effect of topical vitamin A ointment upon the healing of corneoscleral incisions, rabbits were incised bilaterally. After adequate healing time had elapsed, wound strength was assessed by measuring bursting tensile strength. Retinol palmitate 0.5% ointment was applied bid to the right eyes of five rabbits and plain petrolatum ointment was applied to the left eyes. After 13 days, no significant increase in wound strength was found between eyes. However, retinol palmitate 0.1% ointment, when applied tid to the right eyes of nine incised rabbits, was found to double wound strength at 13 days (P less than .0001). This latter strength was repeated in double-blind fashion in five rabbits. After 13 days, wound strength was increased by a factor of 1.45 (P less than .05). Thus we conclude that retinol palmitate 0.1% ointment increases wound strength in healing corneoscleral incisions.
