Users' questions

Is CAP a promoter?

Is CAP a promoter?

Transcription activation by CAP At Class I CAP-dependent promoters, the DNA site for CAP is located upstream of the core promoter. The best-characterized Class I CAP-dependent promoters are the lac promoter and the artificial promoter CC(−61.5), each of which has a DNA site for CAP centered at position −61.5.

What is CAP transcription?

Catabolite activator protein (CAP; also known as cAMP receptor protein, CRP) is a trans-acting transcriptional activator that exists as a homodimer in solution. CAP activates transcription through protein-protein interactions with the α-subunit of RNA Polymerase.

What is a Class 2 promoter?

A class II gene is a type of gene that codes for a protein. Class II genes have a promoter that may contain a TATA box. Basal transcription of class II genes requires the formation of a preinitiation complex. They are transcribed by RNA polymerase II, include both intron and exon, and code for polypeptide.

What is the role CAP catabolite activator protein?

Catabolite activator protein (CAP), also known as cyclic AMP receptor protein (CRP), is activated by cyclic AMP and stimulates synthesis of the enzymes that break down non-glucose food molecules.

What does CAP do in a cell?

The cap protects the 5′ end of the primary RNA transcript from attack by ribonucleases and is recognized by eukaryotic initiation factors involved in assembling the ribosome on the mature mRNA prior to initiating translation.

Is CAP a transcription factor?

The Escherichia coli cyclic AMP receptor protein (CRP or catabolite activator protein, CAP) provides a textbook example of bacterial transcriptional regulation and is one of the best studied transcription factors in biology.

How do gene promoters work?

A promoter is a sequence of DNA needed to turn a gene on or off. The process of transcription is initiated at the promoter. Usually found near the beginning of a gene, the promoter has a binding site for the enzyme used to make a messenger RNA (mRNA) molecule.

What is bacterial promoter?

Promoters in bacteria contain two short DNA sequences located at the -10 (10 bp 5′ or upstream) and -35 positions from the transcription start site (TSS). Their equivalent to the eukaryotic TATA box, the Pribnow box (TATAAT) is located at the -10 position and is essential for transcription initiation.

Where does the CAP activator bind?

Catabolite activator protein (CAP) must bind to cAMP to activate transcription of the lac operon by RNA polymerase. CAP is a transcriptional activator with a ligand-binding domain at the N-terminus and a DNA -binding domain at the C-terminus.

How does lac repressor work?

The lac repressor is a protein that represses (inhibits) transcription of the lac operon. When lactose is not available, the lac repressor binds tightly to the operator, preventing transcription by RNA polymerase. However, when lactose is present, the lac repressor loses its ability to bind DNA.

What does the 5 CAP do?

The 5′ cap is added to the first nucleotide in the transcript during transcription. The cap is a modified guanine (G) nucleotide, and it protects the transcript from being broken down. It also helps the ribosome attach to the mRNA and start reading it to make a protein.

What is CAP medicine?

Outpatient treatment for CAP in patients with no comorbidities and no risk factors for drug-resistant S pneumoniae frequently includes the following: Amoxicillin 1 g PO three times a day OR. A macrolide (azithromycin 500 mg once and then 250 mg daily, clarithromycin 500 mg twice daily) OR. Doxycycline 100 mg twice …

Is there an alternate form of cap-dependent mRNA?

Translation initiation of most mammalian mRNAs is mediated by a 5′ cap structure that binds eukaryotic initiation factor 4E (eIF4E). However, inactivation of eIF4E does not impair translation of many capped mRNAs, suggesting an unknown alternate mechanism may exist for cap-dependent but eIF4E-independent translation.

How are DAP5 and EIF3D essential for cap-dependent mRNA translation?

In vitro translation and ribosome complex studies demonstrate that DAP5 and eIF3d are both essential for eIF4E-independent capped-mRNA translation. These studies disclose a widespread and previously unknown mechanism for cap-dependent mRNA translation by DAP5-eIF3d complexes.

Which is co-dependent on DAP5 and EIF3D?

In vitro translation and 48S complex isolation studies demonstrate that translation of these DAP5-dependent mRNAs is also co-dependent on eIF3d, which occurs through its direct interaction with DAP5.