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Biomedical subjects

L R Taylor

Publications and source records attributed to L R Taylor.

12 recordsLinked to original sources
PubMed1995

Impaired energy homeostasis in C/EBP alpha knockout mice.

Mice homozygous for the targeted deletion of the c/ebp alpha gene, which expresses the CCAAT/enhancer-binding protein alpha (C/EBP alpha), did not store hepatic glycogen and died from hypoglycemia within 8 hours after birth. In these mutant mice, the amounts of glycogen synthase messenger RNA were 50 to 70 percent of normal and the transcriptional induction of the genes for two gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, was delayed. The hepatocytes and adipocytes of the mutant mice failed to accumulate lipid and the expression of the gene for uncoupling protein, the defining marker of brown adipose tissue, was reduced. This study demonstrates that C/EBP alpha is critical for the establishment and maintenance of energy homeostasis in neonates.

Adipose Tissue↗
PubMed1995

Autoregulation of the human C/EBP alpha gene by stimulation of upstream stimulatory factor binding.

The human C/EBP alpha gene promoter shares significant sequence homology with that of the mouse but has a different mechanism of autoregulation. Activation of the murine promoter by direct binding of C/EBP alpha to a site within 200 bp of the transcriptional start was shown to elevate activity by approximately threefold (R. J. Christy, K. H. Kaestner, D. E. Geiman, and M. D. Lane, Proc. Natl. Acad. Sci. USA 88:2593-2597, 1991; K. Legraverend, P. Antonson, P. Flodby, and K. G. Xanthapoulos, Nucleic Acids Res. 21:1735-1742, 1993). Unlike its murine counterpart, the human C/EBP alpha gene promoter does not contain a cis element that binds the C/EBP alpha protein. Neither C/EBP alpha nor C/EBP beta (NF-Il-6) binds the human C/EBP alpha promoter within 437 bp. However, cotransfection studies show that C/EBP alpha stimulates transcription of a reporter gene driven by 437 bp of the C/EBP alpha promoter. Our studies show that the human C/EBP alpha protein stimulates USF to bind to a USF consensus element within C/EBP alpha promoter and activates it by two- to threefold. We propose that the human gene employs the ubiquitously expressed DNA-binding protein factor USF to carry out autoregulation. Autoregulation of the human C/EBP alpha promoter was abolished by deletion of the USF binding site, CACGTG. Expression of human C/EBP beta following transfection did not stimulate USF binding. These studies suggest a mechanism whereby tissue-specific autoregulation can be achieved via a trans-acting factor that is expressed in all cell types. Thus, direct binding of the C/EBP alpha protein to the promoter of the C/EBP alpha gene is not required for autoregulation.

Amino Acid Sequence↗
PubMed1992

Linguistic evidence indicative of authorship by a member of the deaf community.

Documents authored by Deaf Americans were examined in order to determine if linguistic evidence indicative of this group of people is present. The native language of deaf people is not English, but rather American Sign Language (ASL). ASL is a visual-gestural language with its own principles of syntax. The evidence examined includes vocabulary, syntax, and word usage. Such characteristics are class evidence and are not a means of identification, but rather an investigative tool. Such information may be of assistance to the field investigator in either developing a suspect or limiting the number of initial suspects in a case. This research revealed that the use of ASL syntax and idioms and the problems associated with the use of English as a second language are indicative of authorship by a member of the Deaf Community. The results of this research will be of assistance to Document Examiners should they need to determine if a document was authored by a deaf individual.

Adult↗
PubMed1977

Aggregation, migration and population mechanics.

A concept is developed for the regulation of populations by density-dependent movement, rather than by overt competition alone. Fitness is seen as maximising the reproductive advantage of a balance between migratory and congregatory behaviours. Population density is shown to be spatially, as well as temporally dynamic and a mechanism is proposed that accounts for observed spatial behaviour.

Animals↗