Spectrin, the predominant component of the membrane skeleton of the red cell, is essential in determining the properties of the membrane including its shape and deformability. It consists of 2 nonidentical subunits, alpha (MW 240,000) and beta (MW 225,000). Spectrin is present in the red cell membrane in a tetrameric or possibly higher polymeric form through head-to-head self-association of heterodimers that are linked by actin polymers and protein 4.1 to form a 2-dimensional network. Ankyrin binds the skeleton to the membrane lipid bilayer through its high-affinity association with spectrin beta-chains and the integral protein band 3 of the lipid bilayer
NCBI Summary:
Spectrin is an actin crosslinking and molecular scaffold protein that links the plasma membrane to the actin cytoskeleton, and functions in the determination of cell shape, arrangement of transmembrane proteins, and organization of organelles. It is a tetramer made up of alpha-beta dimers linked in a head-to-head arrangement. This gene is one member of a family of alpha-spectrin genes. The encoded protein is primarily composed of 22 spectrin repeats which are involved in dimer formation. It forms weaker tetramer interactions than non-erythrocytic alpha spectrin, which may increase the plasma membrane elasticity and deformability of red blood cells. Mutations in this gene result in a variety of hereditary red blood cell disorders, including elliptocytosis type 2, pyropoikilocytosis, and spherocytic hemolytic anemia. [provided by RefSeq, Jul 2008]
General function
Cell adhesion molecule, Intracellular protein transport, Cytoskeleton
Comment
It encodes a calcium ion binding involved in cell-cell adhesion which is a component of the spectrin . Similar sequences have been identified in Caenorhabditis elegans , Gall , Homo sapiens , Mus musculus and Saccharomyces cerevisiae . It has been sequenced and its amino acid sequence contains a EF-hand family . It has been mapped cytologically to 62B4 . There are 23 recorded alleles : 8 in vitro constructs (none available from the public stock centers), 14 classical mutants (none available from the public stock centers) and 1 wild-type. Loss-of-function mutations have been isolated which affect the cuprophilic cell , the midgut interstitial cell , the germ-line clone germline cyst and 9 other listed tissues and are larval recessive lethal, somatic clone female sterile, somatic clone mitotic, recessive hypoactive and neurophysiology defective. a-Spec is discussed in 152 references (excluding sequence accessions), dated between 1987 and 2002. These include at least 11 studies of mutant phenotypes , 2 studies of wild-type function and 4 molecular studies . Among findings on a-Spec function, the organisation of membrane skeletal proteins is more dependent on a-Spec in the fusome than at the plasma membrane in other cells.
Cellular localization
Plasma membrane
Comment
Ovarian function
Germ cell development, Oogenesis
Comment
cyst formation
Expression regulated by
Comment
Ovarian localization
Primordial Germ Cell
Comment
Follicle stages
Comment
Transcriptomic Analysis of Ovaries from Pigs with High And Low Litter Size. Zhang X et al. (2015) Litter size is one of the most important economic traits for pig production as it is directly related to the production efficiency. Litter size is affected by interactions between multiple genes and the environment. While recent studies have identified some genes associated with prolificacy in pigs, transcriptomic studies of specific genes affecting litter size in porcine ovaries are rare. In order to identify candidate genes associated with litter size in swine, we assessed gene expression differences between the ovaries of Yorkshire pigs with extremely high and low litter sizes using the RNA-Seq method. A total of 1 243 differentially expressed genes were identified: 897 genes were upregulated and 346 genes were downregulated in high litter size ovary samples compared with low litter size ovary samples. A large number of these genes related to steroid hormone regulation in animal ovaries, including 59 Gene Ontology terms and 27 Kyoto Encyclopedia of Genes and Genomes pathways involved in steroid biosynthesis and ovarian steroidogenesis. From these differentially expressed genes, we identified a total of 11 genes using a bioinformatics screen that may be associated with high litter size in Yorkshire pigs. These results provide a list of new candidate genes for porcine litter size and prolificacy to be further investigated.The 10 most differentially expressed genes (log2FoldChange ≥4) from the total of 1 243 DEGs identified between the high and low litter size samples were: homogentisate 1,2 dioxygenase (HGD); phosphoenylpyruvate carboxykinase (PCK1), HSD17B2; early growth response 4 (EGR4), a member of the ras oncogene family (RAB33A); solute carrier protein family 6 (SLC6A20B); zinc finger protein (GLI1); U6 spliceosomal RNA (U6); solute carrier protein family 7 (SLC7A11); and spectrin alpha chain eyrythrocytic 1 (SPTA1), respectively
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