Photoreceptor-specific mRNAs in mice carrying different allelic combinations at the rd and rds loci.

Several retinal mRNAs encoding photoreceptor-specific proteins have been examined in congenic lines of mice carrying different allelic combinations at the rd and rds loci, to determine how mRNA expression is affected by the presence of both the rd and rds genes together or by the presence of one or two rd and rds alleles in the visual cells. Slot blots with retinal RNA from 9 to 30 days old C3H +/+, +/+; rd/+, +/+; rd/rd, +/+; +/+, +/rds; +/+, rds/rds; and the rd/rd, rds/rds double homozygous mutant mice were hybridized successively to several [32P]cDNA probes encoding proteins involved in phototransduction. The increases and decreases in the levels of mRNA coding for opsin, the alpha-subunit of transducin, 48 kDa protein and the beta-subunit of cGMP-phosphodiesterase in the heterozygous and homozygous rds and rd mouse retinas reflected the growth and degeneration of the photoreceptor cells.

Laminin-induced retinoblastoma cell differentiation: possible involvement of a 100-kDa cell-surface laminin-binding protein.

Gene and protein expression of Y-79 retinoblastoma cells growing on poly(D-lysine) is switched from a photoreceptor-like to a conventional neuron-like pathway by the basement membrane glycoprotein laminin. Unlike other cell systems where laminin influences differentiation, Y-79 cells can neither attach to nor chemotactically respond to laminin. However, laminin increases attachment to poly(D-lysine).

The molecular biology of IRBP: application to problems of uveitis, protein chemistry, and evolution.

In closing, molecular biology has helped us in the study of uveitis, in defining the parts of the IRBP molecule that cause EAU/EAP. Simple northern and Southern blotting experiments can answer significant questions in the study of gene structure and expression and in relating these to genetic eye diseases. Molecular biology has provided answers to several long-standing cell biology question such as: where is IRBP synthesized, where is the gene expressed, and how is the IRBP polypeptide processed? In considering how mother nature invented the IRBP gene, the gene structure suggests some interesting alternative models, and causes us to speculate about how large proteins may have evolved.

Hypomethylation of the interphotoreceptor retinoid-binding protein (IRBP) promotor and first exon is linked to expression of the gene.

The interphotoreceptor retinoid-binding protein (IRBP) is limited in expression to retinal photoreceptor cells and a subset of pinealocytes. We have obtained a genomic clone containing the entire coding region and 7 kb of 5' flanking sequence. As a first step in studying IRBP gene regulation we have examined the CpG methylation patterns of the entire IRBP gene in expressing and non-expressing human cells.

Organization and expression of the human myelin basic protein gene.

The human brain contains four isoforms of myelin basic protein (MBP), previously identified by cDNA cloning. We have now isolated and characterized genomic clones encoding the human MBP gene. The gene is 45 kb in extent and consists of seven exons.

Isolation and characterization of the gene for myosin light chain two of Drosophila melanogaster.

A recombinant lambda-phage DNA clone containing Drosophila melanogaster sequences encoding the gene for myosin light chain (MLC) two has been isolated from a library of randomly sheared DNA. The Drosophila MLC2 gene is located in region 99E1-3 on the right arm of chromosome 3, several bands removed from the site reported for the other myosin light chain gene at 98B. The MLC2 sequence at 99E1-3 appears to encode all of the isoforms of Drosophila MLC2.