Retinoblastoma essays

Retinoblastoma essays The retinoblastoma families of proteins are key cell cycle regulatory molecules important for the differentiation of various mammalian cell types. The retinoblastoma protein (RB) regulates transcription of a variety of genes either by blocking the activation domain of various activators or by active repression (finding of appropriate promoters). If the RB's function is lost, it will lead to a variety of cancers and defects in the development of certain cell types. Phosphorylation of RB by cyclin and cyclin-dependent kinases leads to dissociation of RB from E2F (protein receptor), allowing progression into the S-phase. RB has also been proven to have the ability to block cell cycle progression from G1- to the S-phase. (Chan et al, 2001) RB is also a general tumor suppressor, which is associated with a central N (A/B) and C-terminal (pocket domains, which are binding sites for RB) that were defined to have the ability to bind cellular and viral proteins that affect the cell division cycle. Mutations in the pocket domain region are often tumorigenic. These pocket domains are also present in homologues structures of RB that exhibit similar protein binding and functional characteristics pertaining to the cell division cycle. Even though these structures bind to other proteins and have conspicuous molecular and cellular characteristics, they both have the ability to restrain cell growth by inhibiting the pocket domain-binding E2F family of transcription factors. These factors are crucial for the expression of genes that are vital for the S-phase of the cell division cycle. (Singh et al, 2001) Nuclear receptors (NRs) represent a super family of structurally and functionally related ligand-inducible transcription factors that deal with different biological events such as development, differentiation, and homeostasis. Members of this family include receptors for thyroid hormones, steroids, and vitamin D. (Chan et al., 2001) ...

How to Register for the SAT

How to Register for the SAT It probably feels like such a big step when you make plans to register for the SAT. First, you have to figure out what the Redesigned SAT even  is,  and then decide between that and the ACT. Then, once youve decided youre going to take the SAT, you need to figure out the  SAT Test Dates and follow these easy instructions to  register to make sure you have a spot on test day.   Benefits of Registering for the SAT Online There are a ton of good reasons to complete your registration online. In most cases, youll have to. Only a few people can complete their registration via the mail. But if you do complete your registration online, youll get an immediate registration confirmation so you wont be left wondering if youve done it correctly or not. Youll also be able to choose your test center and SAT test date in real-time, which gives you immediate access to real-time availability. Youll get online access for corrections to your registration and printing of your admissions ticket, which youll need to bring with you to the testing center. Plus, youll get easy access to  Score Choiceâ„ ¢ to select scores from prior test dates to send to colleges, universities, and scholarship programs.   How To Register for the SAT Online In order to register for the SAT online, complete the following steps: Set aside 45 minutesGo to the SAT registration website  or ask your high school counselor for flyers that explain how to register.  Click Sign-up Now once youve entered the website.Create a College Board Profile (Stuff youll need to know before you begin!)Pay!Receive your registration confirmation and youre finished! Qualifications to Register for the SAT by Mail Not just anyone can register by mail. You have to meet some qualifications. In order to register for the SAT by mail,  one or more of the following has to be true: You want to pay by check or money order. You obviously cant do that online.  You are younger than 13. In fact, if youre testing and youre under the age of 13, the College Board requires you to register via mail.You need to test on a Sunday for religious reasons for the first time. If its your second time testing on a Sunday, you can register online.  There isnt a test center near your home. You can request a test center change via mail, but you cant online. On the registration form, enter code 02000 as your first-choice test center. Leave the second-choice test center blank.Youre testing in  certain countries  that dont have online registration available or are registering through an international representative.You cant upload a digital photo of yourself. If you dont have access to a digital camera or phone, then you can mail in an approved photo with your paper registration. How To Register for the SAT by Mail Obtain a copy of the SAT Paper Registration Guide in your guidance counselors office.Find the College Board code numbers for college majors youre interested in, college and scholarship programs, test centers and high schools. You can find these code numbers on the College Board website by doing a code search or you can ask for the list of codes in your guidance counselors office.Look up your country code. The US code is 000.