WormMine: ExpressionPattern Expr9948

• Pattern: LET-4::GFP was expressed in a subset of epithelial cells, including epidermal, vulval and rectal cells and the excretory duct and pore. Expression began around the ventral enclosure stage of embryogenesis and continued through larval development, but then decreased in adulthood. Expression was absent from internal epithelia such as the gut and pharyngeal tubes. LET-4::GFP was transiently expressed in the excretory canal cell at the 1.5-fold stage, but no longer visible in this cell by hatch. Notably, with the exception of the canal cell, the epithelia that expressed LET-4 were those that would eventually become cuticle-lined.
• Primary Identifier: Expr9948
• Subcellular Localization: In almost all epithelia where it was expressed, LET-4::GFP appeared strongly apically enriched. In the excretory duct and pore, LET-4::GFP lined the luminal membrane. In the epidermis, it was distributed across the apical surfaces of most dorsal and ventral epidermal cells but was observed more weakly or variably in the lateral (seam) epidermis. The fusion was not strongly enriched at apical junctions based on co-visualization with DLG-1/Discs Large::mcherry. The fusion protein partially overlapped with but did not strongly colocalize with transepidermal intermediate filaments at hemidesmosomes. The fusion was present in many large puncta, potentially representing a vesicular compartment trafficking to or from the membrane. Interestingly, the one exception to the apical localization of LET- 4::GFP was the excretory canal cell. At the 1.5-fold stage, when LET-4::GFP was transiently expressed in the canal cell, LET- 4::GFP localized uniformly around the plasma membrane and not to the developing internal lumen.

6 Anatomy Terms

Definition	Name	Synonym	Primary Identifier
female genital.	vulva		WBbt:0006748
Epidermal layer.	hypodermis	epidermis	WBbt:0005733
H-shaped cell associated with the excretory system, largest cell in C. elegans.	excretory cell	excretory canal cell	WBbt:0005812
The outlet of the excretory sinus to the exterior environment through the cuticle, on the ventral side of the head, just behind the nerve ring.	excretory pore	pore	WBbt:0005778
cell that forms the duct of the excretory system.	excretory duct cell	exc duct	WBbt:0004540
These cells include: B, F, Y, U, K' and K. All rectal epithelial cells contain secretory membrane stacks along this region facing the lumenal cuticle and produce some portion of the cuticular lining of the rectum. These are interfacial cells that connect the alimentary system to the main body syncytium.	rectal epithelial cell	rectal epithelium	WBbt:0008182

1 Genes

WormBase Gene ID	Gene Name	Sequence Name	Organism
WBGene00002282	let-4	C44H4.2	Caenorhabditis elegans

3 Life Stages

Remark	Definition	Other Name	Public Name	Primary Identifier
	The stage that begins when a C.elegans individual is fully-developed and has reached maturity.		adult Ce	WBls:0000041
	The whole period of embryogenesis in the nematode Caenorhabditis elegans, from the formation of an egg until hatching.		embryo Ce	WBls:0000003
	A developmental life stage of the nematode Caenorhabditis elegans that occurs from egg hatching until adulthood.		larva Ce	WBls:0000023