The Baculoviral Genome

FERRELLI MARÍA LETICIA; BERRETTA MARCELO FACUNDO; BELAICH MARIANO NICOLÁS; PABLO DANIEL GHIRINGHELLI; ALICIA SCIOCCO-CAP; VÍCTOR ROMANOWSKI

Viral Genomes - Molecular Structure, Diversity, Gene Expression Mechanisms and Host-Virus Interactions

InTech (University Campus STeP Ri Slavka Krautzeka 83/A 51000 Rijeka, Croatia)

Año: 2012; p. 3 - 32

Baculoviruses are large DNA viruses that cause a lethal disease to larvae of insects mainly from the order Lepidoptera. Their genomes are circular double stranded DNA molecules of about 80 to 180 kbp packed in rod-shaped nucleocapsids. These are enveloped in two possible types of virion phenotypes which are produced in different stages of the larval infection. Baculoviruses encode in their genomes 80 to 180 proteins that include replication, transcription, structural, auxiliary and unknown function proteins. With the increasing sequence data, of almost 60 complete genomes available at present, it was possible to determine a group of 31 core genes which are present in all baculoviruses sequenced so far. Also, this sequences information has led to the classification of the family Baculoviridae in four genera: Alpha-, Beta-, Gamma-, and Delta-baculovirus. Another characteristic of most baculoviruses is the presence of sequences interspersed thorughout the genome which are known as homologous regions (hrs), thought to be involved in transcription enhancement and to play a role in replication. Most recently evidence was found of micro-RNAs being encoded in baculovirus and that were well conserved in a group of closely related baculovirus. This suggests that their existence plays a key role in the baculovirus cycle.