WormMine: ExpressionPattern Expr3918

• Pattern: SMA-1 spectrin first appears in hypodermal cell precursors located on the dorsal surface of the embryo prior to enclosure. SMA-1 is present in the hypodermal cells as they enclose the embryo, and continues to be expressed in the dorsal, lateral, and ventral hypodermal cells throughout embryogenesis. SMA-1 is also expressed in gut and pharynx cells prior to embryonic enclosure, and throughout embryogenesis. In sma-1(ru18) null mutant embryos, both immunoblot and in situ immunofluorescence staining show no signal, demonstrating the antiserum is specific for SMA-1 protein.
• Primary Identifier: Expr3918
• Remark: No detailed description on expression pattern in other life stages. The protein localization patterns observed using SMA-1 antisera are consistent with mRNA in situ expression data (see Expr1425), except in the excretory canal cell, where sma-1 mRNA is present during embryogenesis, but SMA-1 protein expression is delayed until the L1 stage. The timing of SMA-1 protein expression precisely correlates with the period when the excretory cell begins to rapidly elongate, during the first larval stage of development.
• Subcellular Localization: During early morphogenesis, as the hypodermal cells migrate to enclose the embryo, SMA-1 is present at all epithelial cell boundaries, with some protein in the cytoplasm. Once enclosure is complete, SMA-1 protein localizes to the apical membrane of hypodermal, pharyngeal, and gut cells where it remains during embryonic elongation. SMA-1 is found in a speckled pattern at the apical surface of the both dorsal/ventral and seam hypodermis, with increased intensity near cell boundaries. The reorganization of SMA-1 in the hypodermis is concurrent with a change in the organization of actin, from cortical arrays to parallel bundles associated with the apical membrane.

3 Anatomy Terms

Definition	Name	Synonym	Primary Identifier
A chain of very large cuboidal cells forming a wide central lumen in which food arrives from the posterior pharynx, is digested, and from which waste products proceed to the rectum. Intestinal rings form in groups of two and four cells surrounding the common lumen; thus the epithelium is only one cell deep at any point, with neighboring cells firmly secured to their neighbors by apical adherens junctions. These cells have very large nuclei and many large vacuoles, yolk granules, and other inclusions; the latter increase in number and electron density as the animal ages.	intestine	gut	WBbt:0005772
Epidermal layer.	hypodermis	epidermis	WBbt:0005733
the feeding organ, a neuro-muscular pump in the head of the animal, used to ingest food, bacteria suspended in liquid, filter them out, grind them up and transport posteriorly into the instestine.	pharynx	esophagus	WBbt:0003681

1 Genes

WormBase Gene ID	Gene Name	Sequence Name	Organism
WBGene00004855	sma-1	R31.1	Caenorhabditis elegans

2 Life Stages

Remark	Definition	Other Name	Public Name	Primary Identifier
	The first stage larva. At 25 Centigrade, it ranges 14-25.5 hours after fertilization, 0-11.5 hours after hatch.		L1 larva Ce	WBls:0000024
	The whole period of embryogenesis in the nematode Caenorhabditis elegans, from the formation of an egg until hatching.		embryo Ce	WBls:0000003