16 - parvo - notes.docx

3 Pages
74 Views
Unlock Document

Department
Molecular Genetics and Microbiology
Course
MGY378H1
Professor
Alan Cochrane
Semester
Winter

Description
MGY378 – DNA viruses – February 27, 2012 Will not discuss baculovirue; iridoviruses; but rest, excluding hepadna, will be discussed Relative size of viruses – very different – Capsid – most are icosahedral; others are helical, complex - Pox virus does not resemble any other virion Envelope or not – small viruses are naked, no envelope - Herpes and pox are enveloped Single stranded or double stranded – all genomes are double stranded except for parvoviruses of viruses to be discussed Papova is old nomenclature – papilopma and polyomaviruses initially grouped together into one family because close resemblance – similar size, characteristics, etc – but some fundamental differences Only pox virus brings in its own RNA polymerase – life cycle in cytoplasm – others live in nucleus - Other viruses wil have exposure to DNA polymerase, - Pox does not have that exposure – need to have extra “luggage” Correlation some between size of virion and size of genome PARVOVIRUS - Large group of viruses – widespread in variety of animals - Two big subfamily – one infects vertebrates, other infects insects Parvovirus – first in vertebrate virus – no human counterpart in this subfamily - Not to be discussed Amdovirus – causes disease in mink Erythrovirus – B19 associated with disease Bocavirus – HboV1 discovered in 2005 – common in respiratory tract 1 to 4 are autonomous parvoviruses – do not need helper virus to enter cell and replicate Dependovirus – aka AAV – needs helper virus – usually adenovirus, can also be herpesvirus B19 – most ppl have antibodies against this virus – infects precursor cells - Serious issue in haemolytic anemia patients - Commonly found in heart – site of lifelong persistence perhaps? o Cardiac issues? Unsure in literature - Virus can cross placenta and infect fetus – Fifth disease – occurring towards end of B19 infection - Red rash on cheeks – resolves on its own - Immune complexes build up in joints in adult – also tends to resolve on its own Virion - Very small – smallest DNA viruses - No envelope - Small enough to fit through nuclear pore – only DNA virus able to do this Genome - Linear single stranded but ends have particular structure, called T shaped structure due to complementarity of sequence o Base paired o T shape on both ends - In autonomous viruses – only encapsidate minus strand – complementary to one used as mRNA o Both have T shaped structure but the sequences different – directionality – and proteins can distinguish the strands - AAV – encapsidate either strand – approximately equal frequency – ends are inverted terminal repeats of each other Gene expression - Genome organized into two half – one half for structural proteins o VP are the capsids - Other proteins involved in replicating genome o Rep and number Infection - Recognize cell surface receptor - Endocytosis – uptake via endosome – - Acificiation - Breaking and releasing the capsids with genome still inside - Move with aid of microtubules ot nuclear pore and enter - DNA then come out depending on virus – - Permissivity of infection determined in several ways - dsDNA used for gene expression – amplify and make more copies of viral geome - needs to be in S phase of cell cycle for all this to occur Autonomous parvoviruses - require cells to enter S phase to replicate o no method to induce cell into S phase - DNA remains in capsid until S phase starts - For AAV, needs helper virus o Could not identify particular adenovirus protein o Suggesting not a particular viral protein ne
More Less

Related notes for MGY378H1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit