Search PubMed⌕ Search

Biomedical subjects

M F Peters

Publications and source records attributed to M F Peters.

24 records · Page 2Linked to original sources
PubMed1994

beta 2-Syntrophin: localization at the neuromuscular junction in skeletal muscle.

The syntrophins are a multigene family of proteins which bind C-terminal domains of dystrophin, utrophin and homologs thereof. We report here that antibodies specific for one isoform, beta 2-syntrophin, labeled only the neuromuscular junction (NMJ) in rat skeletal muscle. Anti-alpha 1-syntrophin antibodies gave strong labeling of the sarcolemma and NMJ in normal rat and mouse muscle, and similar but much weaker labeling in dystrophin-minus mdx muscle. beta 2-Syntrophin therefore appears to be specific to the NMJ in normal muscle, as is utrophin, and may be involved in acetylcholine receptor clustering. alpha 1-Syntrophin appears to be associated mainly with dystrophin, as expected, but a small portion must be associated with another protein, possibly homologs of the electric tissue 87K protein.

Amino Acid Sequence↗
PubMed1993

Two forms of mouse syntrophin, a 58 kd dystrophin-associated protein, differ in primary structure and tissue distribution.

Syntrophin, a 58 kd extrinsic membrane protein, is concentrated at postsynaptic sites at the neuromuscular junction and may be involved in clustering acetylcholine receptors. In muscle and nonmuscle tissues, syntrophin is associated with dystrophin, utrophin, and two homologs of the dystrophin carboxy-terminal region. We have isolated three cDNAs encoding Torpedo and mouse syntrophins. The Torpedo cDNA encodes a full-length protein, and on Northern blots recognizes a 3.5 kb mRNA. The two mouse syntrophin cDNAs are products of separate genes but encode proteins that share 50% identity. Syntrophin-1 mRNA (2.2 kb) is expressed at highest levels in skeletal muscle. Syntrophin-2 mRNAs (2.2, 5.0, and 10 kb) are expressed in all mouse tissues examined. These patterns of expression suggest that syntrophin-1 and syntrophin-2 may associate with different members of the dystrophin family.

Amino Acid Sequence↗
PubMed1979

Induction of erythropoietin responsiveness in vitro by a distinct population of bone marrow cells.

Bone marrow contains a small population of primitive erythroid progenitor cells which can be detected by their capacity to form large numbers of erythroid progeny in viscous cultures containing erythropoietin (EP). These cells have been termed erythroid 'burst-forming units' (BFUe). The present study demonstrates that expression of the erythroid differentiation potential of BFUe requires the presence of an activity additional to EP. This activity has been designated as BFA (burst feeder activity). It is shown that the number of BFUe detected and their apparent sensitivity to EP are directly related to the BFA concentration of the cultures. BFA was found to be associated with a population of bone marrow cells of high buoyant density and small volume, which are sensitive to irradiation. The radiation dose-effect curve provided strong evidence that bone marrow BFA is independent of cell proliferation; this was supported by showing that BFA is unaffected by in vivo treatment with hydroxyurea. The findings are compatible with a two-step regulation model for erythroid differentiation in which BFA-induced progeny of BFUe acquire sensitivity to EP.

Animals↗
PubMed1978

Effects of human leukocyte conditioned medium on mouse haemopoietic progenitor cells.

Medium conditioned by human peripheral blood leukocytes (HLCM) was studied for its in vitro effects on haemopoietic progenitor cells (CFU-s and CFU-c) present in mouse bone marrow. HLCM has poor colony stimulating activity in semi-solid cultures of mouse bone marrow cells, but invariably increases the number of colonies obtained in the presence of plateau levels of semi-purified colony stimulating factor (CSF). In liquid cultures, HLCM appears to contain a potent initiator of DNA synthesis in CFU-s, an activity which coincides with an increased CFU-s maintenance and causes a three- to four-fold increase in CFU-c number. It is apparent from this study that HLCM, in addition to stimulating colony formation in cultures of human bone marrow cells, has a profound in vitro effect on primitive haemopoietic progenitor cells of the mouse, which cannot be attributed to CSF.

Animals↗