Acetylcholinesterase and Butyrylcholinesterase Expression in Adult Rabbit Tissues and During Development

Abstract

A large cDNA fragment covering the complete sequence of the mature catalytic subunit of rabbit acetylcholinesterase (AChE) has been cloned and sequenced. This sequence was compared to that of rabbit butyrylcholinesterase [BChE;Jbilo, 0. & Chatonnet, A. (1990) Nucleic Acids Res. 18, 39901. Amino acid sequences of AChE and BChE have 51% identity. They both possessed a choline-binding site W84, a catalytic triad S200-H440-E327 and six cysteine residues (positions 67 -94, 254-265, 402-521) in conserved sequence positions to those that form three intrachain disulfide bonds in all cholinesterases (by convention, numbering of amino acids is that used for Torpedo AChE). Rabbit AChE had a larger number of aromatic residues lining the active-site gorge than rabbit BChE (14 compared to 8, respectively) and a smaller number of potential N-glycosylation sites (3 compared to 8, respectively). Both catalytic subunits have a hydrophilic C-terminus (catalytic subunits of type T). Expression of acetycholinesterase and butyrylcholinesterase genes (ACHE and BCHE) was studied in rabbit tissues and during development by a correlation of Northern-blot analysis and enzymic activities. This correlation was rendered difficult by the presence of an eserineresistant esterase active on butyrylthiocholine in serum, liver and lung. When the contribution of this carboxylesterase was taken into account, brain was found as the richest source of BChE followed by lung and heart. Rabbit liver had a very low content of BChE that correlated with the low BChE activity in plasma. During development, BCHE transcripts were detected as early as day 10 post coitum, whereas ACHE transcripts appeared only on day 12.Acetylcholinesterase belongs to a large family of proteins with conserved overall structure [l]. Functions of those proteins range from cell adhesion (as exemplified by glutactin and neurotactin) to detoxification (as liver carboxylesterases) and to the rapid hydrolysis of acetylcholine and other choline esters (cholinesterases). In vertebrates, two related enzymes : acetylcholinesterase (ACE) and butyrylcholinesterase (BChE) are able to hydrolyze acetylcholine and are inhibited by 0.01 mM eserine. Both enzymes present the same molecular forms, including globular and asymmetric molecules (reviews in [2, 31). The mechanisms of choline ester hydrolysis are basically the same in both enzymes [4] ; the substrate is directed to the bottom of a deep gorge by a series of aromatic Abbreviations. AChE and BChE, acetylcholinesterase and butyrylcholinesterase enzymes ; ACHE and BCHE, genes encoding AChE and BChE; Brij 96, 10-oleylether; Iso-OMPA, tetranionoisopropylpyrophosphortetramide; LS, LSB, HS and HSB, low salt, low-salt Brij, high salt and high-salt Brij buffers.

Characterization of acetylcholinesterase and butyrylcholinesterase forms in normal and dystrophic Lama2dy mouse heart

“…In agreement with previous results obtained from rat (Nyquist-Battie et al, 1987) and rabbit (Jbilo et al, 1994) heart extracts, the mouse cardiac tissue was richer in BuChE than AChE activity. Moreover, AChE activity was lower in mouse heart (0.03-0.05 U/mg) than in skeletal muscle (0.15-0.20 U/mg, Cabezas-Herrera et al, Fig.…”

Monoclonal antibodies to human butyrylcholinesterase reactive with butyrylcholinesterase in animal plasma

“…Our results support the conclusion of Jbilo et al [30] that the butyrylthiocholine hydrolase that migrates adjacent to albumin in Figure 3 (lanes 11 and 12) is rabbit carboxylesterase. The carboxylesterases in horse, cat, tiger, rabbit, guinea pig, mouse, and rat plasma consistently migrate adjacent to albumin and stain with alpha-naphthylacetate.…”

“…A previous report named the rabbit plasma carboxylesterase “monomeric BChE” [29]. However, Jbilo et al concluded that “monomeric BChE” in rabbit plasma is carboxylesterase [30]. The rabbit plasma carboxylesterase did not bind to procainamide-affinity gel, it was not inhibited significantly by the specific BChE inhibitors eserine and iso-OMPA, and it preferred indoxyl acetate as a substrate.…”

“…Rabbits deficient in atropine esterase do not have a band of butyrylthiocholine hydrolase activity adjacent to albumin on a nondenaturing gel [30]. The atropine esterase in rabbit serum is a carboxylesterase with a molecular weight of 65,000, similar to the molecular weight of albumin.…”

Role of Intronic E- and N-box Motifs in the Transcriptional Induction of the Acetylcholinesterase Gene during Myogenic Differentiation

“…Given that AChE is an excellent marker of synaptic differentiation, several groups have recently begun to decipher the molecular basis underlying these changes in AChE expression. For example, increases in AChE mRNA expression have previously been reported during myogenic differentiation (5)(6)(7)(8)(9). Moreover, activity-induced changes in AChE transcript levels have been observed in both cultured myotubes as well as in skeletal muscle in vivo (10 -14).…”