Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Simian virus 40-transformed rabbit spleen cell TRSC-1 synthesizes intracellular whole IgG molecules of the alb4 allotype. Two hypoxanthine-guanine phosphoryl transferase-deficient mutants were derived from this line. One of these, TRSC-1-8, was used in somatic cell fusion experiments together with gangliocytes from a rabbit immunized against beta-galactosidase. Out of nineteen hybrid clones surviving in selective medium, only one, L17, was shown to produce free gamma chains which express the a2 allotype of the donor rabbit rather than the al marker of the parents TRSC-1-8 line. The inability to restore IgG secretion in hybrids suggests that dominant regulatory controls are exerted by the TRSC-1 genome on Ig reduction. This supports the notion that the TRSC-1 line originated from a splenocyte that had not reached the final plasmocyte differentiation stage at the time of viral transformation.
 ...
PMID:Switched allotype expression in an immunoglobulin-nonsecreting rabbit lymphoid cell line fused with rabbit gangliocytes. 702 Nov 64

The murine Pax3 gene encodes a transcription factor containing a paired domain as well as a paired-type homeodomain. Its expression during embryonic development is temporally and spatially restricted, including mainly the dorsal part of the neural tube, the mesencephalon, the neural crest derivatives, and the dermomyotome. Development in the absence of Pax3 can be studied in Splotch mutant mice, which bear mutations within the Pax3 gene. Various alleles have been phenotypically and molecularly characterized. Abnormalities have been observed in the brain, the neural tube, the trunk neural crest derivatives and in muscles of these mutants. The importance of PAX3 during human embryonal development is readily seen in Waardenburg patients, who present a dominant inherited syndrome consisting mainly of craniofacial abnormalities, pigmentation deficiencies, and deafness, consecutive to PAX3 mutations. In order to analyze the nervous system of Splotch embryos in more detail, we employed the transgenic mouse line L17. These transgenic mice harbor a beta-galactosidase marker gene under the control of Hoxa-7 promoter elements. Probably in combination with cis-elements adjacent to the integration site of the L17 transgene, the Hoxa-7 elements drive the expression of the marker gene in major parts of the peripheral nervous system, as well as in more restricted parts of the central nervous system. These structures can be visualized during embryonic development, allowing detailed neuroanatomical studies in midgestation embryos. We describe the beta-galactosidase expression in wild-type L17 mice and demonstrate the applicability of L17 mice to the study of the nervous system. We then apply this experimental system to the analysis of Splotch embryos. Our findings underline the importance of Pax3 in the development of neural crest-derived structures, especially of cranial ganglia and nerves. We suggest the use of L17 mice as a valuable tool to perform similar analysis for other embryonal mutant phenotypes.
 ...
PMID:A transgenic neuroanatomical marker identifies cranial neural crest deficiencies associated with the Pax3 mutant Splotch. 755 16

Exposure of midgastrulation mouse embryos to retinoic acid induced anteriorized expression of the Hoxa-1 (Hox-1.6) and Hoxb-1 (Hox-2.9) genes. Separate, extra domains of Hoxb-1 expression were detected as stripes and patches up to the midbrain boundary within rhombomeres r3, r2, and r1. Morphological alterations were studied in embryos of the transgenic line L17, which allowed staining of cranial ganglia, motor neurons, and axons by means of the beta-galactosidase reaction. Axons of motor neurons in r3 normally project laterally, before they turn sharply rostrally to exit with the trigeminal nerve from r2. Altered projection patterns were observed for single neurons, groups of neurons, or the complete set of r3 motor neurons in different embryos exposed to retinoic acid. Here r3 axons turned in the opposite direction and exited as facial nerves from r4. These changes of neuroectodermal fates indicate a linkage between axonal pathfinding and intrinsic neuronal specification by Hox codes.
 ...
PMID:Reversal of axonal pathways from rhombomere 3 correlates with extra Hox expression domains. 809 85