Cold sensitive for fermentation protein 1 (Csf1) is a fungal membrane protein required for fermentation at low temperature []. It may be involved in the maturation of secretory proteins [].
The CRISPR-Cas system is a prokaryotic defense mechanism against foreign genetic elements. The key elements of this defense system are the Cas proteins and the CRISPR RNA. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) are a family of DNA direct repeats separated by regularly sized non-repetitive spacer sequences that are found in most bacterial and archaeal genomes []. CRISPRs appear to provide acquired resistance against mobile genetic elements (viruses, transposable elements and conjugative plasmids). CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA).The defense reaction is divided into three stages. In the adaptation stage, the invader DNA is cleaved, and a piece of it is selected to be integrated as a new spacer into the CRISPR locus, where it is stored as an identity tag for future attacks by this invader. During the second stage (the expressionstage), the CRISPR RNA (pre-crRNA) is transcribed and subsequently processed into the mature crRNAs. In the third stage (the interference stage), Cas proteins, together with crRNAs, identify and degrade the invader [, , ].The CRISPR-Cas systems have been sorted into three major classes. In CRISPR-Cas types I and III, the mature crRNA is generally generated by a member of the Cas6 protein family. Whereas in system III the Cas6 protein acts alone, in some class I systems it is part of a complex of Cas proteins known as Cascade (CRISPR-associated complex for antiviral defense). The Cas6 protein is an endoribonuclease necessary for crRNA production whereas the additional Cas proteins that form the Cascade complex are needed for crRNA stability []. This entry represents the Csf1 family of Cas proteins. Members of this family show up near CRISPR repeats in Acidithiobacillus ferrooxidans ATCC 23270, Azoarcus sp. (strain EbN1), and Rhodoferax ferrireducens (strain DSM 15236/ATCC BAA-621/T118). In the latter two species, the CRISPR/cas locus is found on a plasmid. This family is one of several characteristic of a type of cas gene cluster we designate Aferr after A. ferrooxidans, where it is both chromosomal and the only type of cas gene cluster found. The gene is designated csf1 (CRISPR/cas Subtype as in A. ferrooxidans protein 1), as it lies closest to the repeats.
This entry represents a macrophage colony-stimulating factor 1 receptor (CSF1R), also known as macrophage colony-stimulating factor receptor (M-CSFR) or CD115 (Cluster of Differentiation 115). CSF1R is a tyrosine-protein kinase that acts as cell-surface receptor for CSF1 and IL34 and plays an essential role in the regulation of survival, proliferation and differentiation of hematopoietic precursor cells, especially mononuclear phagocytes, such as macrophages and monocytes []. CSF-1 and CSF-1R play an important role in the development of the mammary gland and may be involved in the process of mammary gland carcinogenesis []. Mutations in the CSF1R gene cause hereditary diffuse leukoencephalopathy with spheroids, which is an autosomal-dominant central nervous system white-matter disease with variable clinical presentations, including personality and behavioral changes, dementia, depression, parkinsonism, seizures and other phenotypes [].This entry also includes the tyrosine-protein kinase transforming protein v-fms from Feline sarcoma virus. CSF1R (the c-fms product) is its cellular counterpart. It differs in some amino acid substitutions and the replacement of 50 C-terminal amino acids by 11 unrelated residues in v-fms [, , ]. v-fms can bind CSF-1 and has constitutive tyrosine-specific protein kinase activity, providing growth stimulatory signals in the absence of ligand [].
