WormMine: ExpressionPattern Expr3463

• Pattern: The mec-1 promoter expressed GFP in the touch receptor neurons, many lateral neurons (the SDQ, PLN, and ALN neurons and two neurons of the dorsal sublateral cord), the PVT neuron, and the intestinal muscle.
• Primary Identifier: Expr3463
• Remark: Because of the expression in non-touch receptor neurons, mec-1 (also tagged with gfp) was tested whether could rescue the Mec phenotype when expressed from the touch receptor neurons-specific mec-18 promoter. Touch receptor expression was sufficient for rescue (three strains produced 90% +/- 5% touch-sensitive animals; N = 70). LacZ expression was used to test protein topology with respect to the plasma membrane, because cytoplasmic, but not extracellular, beta-galactosidase is active . When lacZ was fused directly after the DNA for the predicted signal sequence, no beta-galactosidase activity was found, suggesting that the resulting fusion protein is extracellular. Insertion of an artificial transmembrane domain after the signal sequence restored activity. beta-galactosidase activity was also absent when lacZ was fused at codon 45, directly after sequence for the weakly predicted transmembrane domain. As before, insertion of a sequence encoding an artificial transmembrane domain before lacZ restored activity. These results suggest that MEC-1 does not contain a transmembrane domain between residues 21 and 41.
• Subcellular Localization: Expression of a full-length MEC-1::GFP protein fusion from the mec-1 promoter rescued the mec-1(e1496) null phenotype and revealed that MEC-1 was processed differently in touch receptor neurons. The fusion protein was visible in the ER of the same non-touch cells seen with the promoter fusion and in some neurons of the ventral cord, but it was not seen along their processes. In contrast, MEC-1::GFP was consistently visible in the ER and along the processes of the touch receptor neurons. In addition, MEC-1::GFP was sometimes seen along the edge of the body wall muscles. Since these cells did not express the promoter fusion, this muscle fluorescence suggests that MEC-1 is a secreted protein.

9 Anatomy Terms

Definition	Name	Synonym	Primary Identifier
neurons that sense body touch, have specialized microtubules in processes.	touch receptor neuron	microtubule cell	WBbt:0005237
Neuron class of one interneuron, projects along ventral cord to ring.	PVT	lineage name: ABplpappppa	WBbt:0004070
Interneuron, associated with PLM	PLNL	lineage name: TL.pppap	WBbt:0004102
Interneuron, associated with PLM	PLNR	lineage name: TR.pppap	WBbt:0004098
intestinal muscle cell, attach to intestine and body wall anterior to anus	intestinal muscle	stomato-intestinal muscle	WBbt:0005796
Ant. lateral interneuron, process projects into ring	SDQR	lineage name: QR.pap	WBbt:0004991
Posterior lateral interneuron, process projects into ring	SDQL	lineage name: QL.pap	WBbt:0004993
Neuron associated with ALM	ALNL	lineage name: ABplapappppap	WBbt:0003939
Neuron associated with ALM	ALNR	lineage name: ABprapappppap	WBbt:0003937

1 Genes

WormBase Gene ID	Gene Name	Sequence Name	Organism
WBGene00003165	mec-1	T07H8.4	Caenorhabditis elegans

0 Life Stages