left-right determination factor 2 (Lefty2), also known as Left-right determination factor A (Lefty A), endometrial bleeding associated factor (left-right determination, factor A transforming growth factor-beta superfamily), and transforming growth factor beta-4, is a member of the TGF-beta family of proteins. This protein is secreted and plays a role in left-right asymmetry determination of organ systems during development. Lefty2/Lefty A may also play a role in endometrial bleeding. Mutations in Lefty2/Lefty A have been associated with left-right axis malformations, particularly in the heart and lungs. Some types of infertility have been associated with dysregulated expression of this gene in the endometrium. Alternative processing of this protein can yield three different products. Depletion of both Lefty1 and Lefty2 causes unchecked Nodal signaling, expansion of mesendoderm, and loss of ectoderm. The expansion of mesendoderm correlates with an extended period of rapid cellular internalization and a failure of deep-cell epiboly. The gastrulation defects of embryos depleted of Lefty1 and Lefty2 result from the deregulation of Squint signaling.

Lefty2 Protein, Mouse, Recombinant (His & Myc) is expressed in E. coli.

Left-right determination factor 2(LEFTY2) is a secreted protein which belongs to the TGF-beta family. Lefty was first identified in a screen for undifferentiated cell-specific cDNAs from the P19 mouse embryonal carcinoma cells. Its mRNA expression on the left side of the developing embryo earned the name “Lefty”. The human orthologue was initially identified as Ebaf, Endometrial bleeding associated factor. Lefty contains the six cysteine residues that are conserved among TGF-β related proteins and that are necessary to form the cysteineknot structure. Its function in patterning left-right asymmetry of the developing organ systems such as the heart and lung is consistent in all vertebrate species examined. Lefty acts as an antagonist to Nodal signaling, potentially by competing for binding to a common receptor. It may play a role in endometrial bleeding.

TDGF1 (CRIPTO) is a member of the epidermal growth factor-Cripto-1/FRL-1/Cryptic (EGF/CFC) gene family and an obligate co-receptor involved in NODAL signaling, a developmental program implicated in midline, forebrain, and left-right axis development in model organisms. Cripto-1 is enriched in a subpopulation of embryonal, melanoma, prostate, and pancreatic cancer cells that possess stem-like characteristics. Therefore, Cripto-1 may play a role during developmental EMT, and it may also be involved in the reprogramming of differentiated tumor cells into cancer stem cells through the induction of an EMT program.

Encapsidates the viral RNA genome by forming a left-handed helical nucleocapsid that protects the RNA from nucleases. RNA replication depends on the availability of soluble nucleoprotein. The encapsidated genomic RNA is termed the NC and serves as template for transcription and replication.

Cryptic (CFC1) is a member of the epidermal growth factor (EGF)- Cripto, Frl-1, and Cryptic (CFC) family. It contains an EGF-like domain, and is glycosylated on its N-terminal during post-translational modification. Cryptic is identified as a NODAL coreceptor involved in the correct establishment of the left-right axis. It may play a role in mesoderm and/or neural patterning during gastrulation. The unnormal expression of this gene may causes a series of diseases such as HTX2, Transposition of the great arteries dextro-looped 2, and Conotruncal heart malformations.

Cerberus 1 is a secreted glycoprotein that forms disulfide-linked homodimers. It is a cytokine member of the DAN domain family of BMP antagonists that includes DAN (DAND1), Gremlin/Drm (DAND2), PRDC (Protein Related to Dan and Cerberus, DAND3), and COCO/Dante (DAND5). DAN family members contain a cysteine knot domain that is homologous to that found in other TGF-beta superfamily ligands. At the onset of gastrulation, Cerberus 1 is transiently expressed in anterior endodermal structures in response to Nodal and Shh. Cerberus 1 binds BMP-4 and Nodal and inhibits their activities. The inhibitory functions of Cerberus favor mesodermal development in the anterior region of the gastrula and suppresses posterior mesodermal differentiation. In chick and Xenopus, Cerberus 1 also regulates, but is not required for embryonic left-right polarization, neurulation, and head and heart induction.